credit for some of the first portion goes to the100poland on tumblr. i added info of my own and redid the in-series timeline to make it more detailed. obviously there are spoilers for the section where it has the rundown of each season

feb 2021 update: i used the timeline from the 100 wiki for the in-series events, but fixed the grammar and added some other events i thought were important.

(also, thank you so much for 1k reads already???? what have i done to deserve this)

HISTORY

1959 - The Mount Weather Emergency Operations Center is founded (it is based on an actual facility, JRoth confirmed it). It is constructed to house senior US officials in the event of a nuclear war.

It is safe to assume Mount Weather was inhabited by descendants of the US government and military officials that survived the nuclear apocalypse in the underground bunker.

It's in Blue Ridge Mountains, Virginia, about 40 miles from Washington, D.C (later TonDC).

2001 - Association football (FIFA) game is played as seen in flashbacks on the Ark. Clarke says it ended 147 years ago.

2019 - Mir-3, predecessor of the Ark, is presumably launched.

2025 - Becca is born.

2040s - Earth loses contact with Asteroid Mining Penal Colony. In South America, Bill Cadogan travels to Peru's Machu Picchu, where he discovered the Anomaly Stone there, in a secret observatory underneath the Temple of the Sun. He decides to bring it to the United States.

The Eligius Corporation is a mining company that transported prisoners to the Asteroid Mining Penal Colony. Jackson mentions to Abby that Becca first developed the Nightblood for the Eligius Mining Company to protect against solar radiation for long space missions, in which criminals were put into hypersleep and were given Nightblood to protect them from radiation. In 4x1 there's an article on screen titled "Contact lost with Asteroid Mining Colony".

The Second Dawn is a Doomsday Cult, that is founded by the cult leader, Bill Cadogan. He believes that the apocalypse is coming and wants humanity to survive. Cadogan builds a bunker that can save approximately 1,200 people. An article titled "Second Dawn Investigation Underway" from the Chicago Weekly Herald can be seen on one of Raven's monitors as she explains 2048 nuclear reactor technology to Jasper and Monty. This is the first mention of the Second Dawn doomsday cult.

2048 - Two dozen mega reactors had been built to withstand any disaster, even a nuclear attack.

2051
Becca creates A.L.I.E. on Oct. 20. She is 26.

That same year, she has to lock up A.L.I.E. because her answer for what was wrong with the world was "too many people".

2052
Fearing A.L.I.E., she decides to continue her research on her space station Polaris. She's trying to perfect A.L.I.E. 2.0, when A.L.I.E. causes the nuclear apocalypse.

The first Praimfaya takes place on May 10, 2052, when Chris accidentally lets A.L.I.E. out. A.L.I.E. successfully launches nuclear missiles from various countries around the world, including 27 missiles from China targeting the U.S.

In the bunker in 2x16, Murphy finds a TV and pushes play. A home movie in the same bunker appears onscreen. Murphy watches as the man explains how he lost control and how "she" got the launch codes. He apologizes before shooting himself dead.

According to Becca, about 6.5 billion people were killed in the aftermath. However, some survivors remained, these included the ancestors to the Grounders, the Mountain Men, and the Sky People.

In the Pilot, Jasper wears a T-shirt with "Earth day 2052″ on it.

2054,  1 Oct. - Unity Day
In addition to A.L.I.E., Becca creates the Nightblood serum and a second version of the AI. In the meantime, commander McAdams is preparing to dock with the other twelve stations to create the Ark, but he fears the AI will infect all 12 stations if it remains on board. Becca pleads that the AI will save them on the Ark and can help human scientists giving them calculations to ensure their survival. Becca locks herself in the lab and inserts the AI chip into her neck. Later, Becca escapes Polaris just before it is destroyed and descends to Earth to become the first Commander. That is why the place where she landed is called Polis (letters "ar" in Polaris were burnt during landing), Grounders' leaders are called Commanders (it was written on Becca's suit) and they have Nightblood (Becca probably injected the survivors she met after landing). In 2150, Murphy analyzes an old escape pod and Grounder cave paintings. From them, he theorizes, that the First Commander came from Polaris.

Becca descends to Earth with ALIE 2.0. A week later, Becca was burned alive by the cult members, led by Bill Cadogan.

Callie Cadogan and some of the Second Dawn members, who are all inoculated with Nightblood, defects from the Second Dawn Bunker and head towards the surface, becoming the ancestors to the Grounders. Bill Cadogan and the other Second Dawn members, who remained in the bunker, open up a portal to Bardo, where they settled there, becoming the ancestors to the Disciples.

2070 - Gabriel Santiago and Russell Lightbourne successfully bring back Josephine Lightbourne using a Nightblood host and her Mind Drive.

2086 - Dante Wallace is born.

2093 - The doors of Mount Weather are opened, 54 people die of radiation, including Dante's sister and mother.

Presumed beginning of the experimentation on Outsiders.

2102 - MIR-3 salvaged and incorporated into The Ark.

Thelonious Jaha is born.

2107 - Marcus Kane is born.
2109 - Abigail Griffin is born.
2126 - Bellamy Blake is born.
2128 - Lexa kom Trikru is born.
2130 - Raven Reyes is born
2131 - Clarke Griffin is born.
2132 - Octavia Blake is born.

2130s - Original Echo is forced by Queen Nia to kill her friend Ash, but failed, so Ash killed her and took her name.

2144 - Madi is born in Shadow Valley.

2147 - Prince Roan is banished by Queen Nia and Lexa as part of a deal to allow the Ice Nation to join the Coalition. Roan hasn't returned to the Ice Nation in three years.

2148 Fall - Catastrophic Life Support System Failure discovered.

Jake Griffin gets floated as he attempts to go public with the discovery.

Clarke Griffin is sent to juvenile detention for treason.

Octavia Blake is sent to juvenile detention for being a second child.

Aurora Blake gets floated for having a second child.

2149
The 100 receive Earth Skills from Pike on The Ark.

The 100 are sent to Earth and land in what was formerly Virginia in the  United States of America.

THE ARK

The 12 nations that formed the Ark:

1.       Australia
2.       Brazil –> Mecha Station
3.       Canada
4.       China (Shenzhen) –> Arrow Station, the airlock, where Jake Griffin was floated (arguable)
5.       France
6.       India
7.       Japan –> Skybox
8.       Russia (Mir-3) –> might be a part of Go-Sci
9.       United Kingdom
10.     United States –>  Government & Science Station (Go-Sci/The Ring), including Ark Station Medical, Earth Monitoring Station and Alpha Station
11.     Uganda
12.     Venezuela

There's also a remembrance book on the Ark, that has The Grounders' names in it. We can see familiar ones: Miller, Blake, Murphy, Jaha, Jordan. The names indicate the nationality of the first residents of the Ark.

- Names of the stations (arguable):
1.       Alpha - Abby, Jake, Clarke, Millers, Jaha, Wells
2.       Farm/Agro - Jasper, Monty, Hannah, Bryan, Pike, Riley
3.       Hydra
4.       Mecha - Raven and Finn
5.       Factory - Aurora, Bellamy, Octavia, Monroe, Mel
6.       Arrow
7.       Power/Tesla
8.       Orchid
9.       Flint
10.     Aero
11.     Go Sci
12.     Prison Station is also known as the Sky Box and Lockup

*Russian and American flags are visible in 1x13 on the sides of the dropship.

On-screen graphics in 1x13 there's Alpha, Arrow, Factory, Hydra, Mecha, Tesla stations as major parts of the Ark.

I think I recognized them properly (Alpha is hidden):

Airlock where Jake Griffin was floated has Chinese writing on it.

There is a Brazilian flag painted on the side of Mecha Station as shown when Abby and Kane go outside.

Japanese flag painted on the Skybox in 1x1.

TIMELINE

- Season 1 starts when the 100 were sent to Earth on Saturday, September 13, 2149.

Sep. 13 - The 100 land on earth 20 miles west of Mount Weather, Virginia, in the Shenandoah Valley. Clarke leads a group to Mount Weather while Bellamy starts setting up The Camp. The Coalition-Skaikru Conflicts unofficially begins with the Delinquents inadvertently invading the Woods Clan territory.

Sep. 14 - Jasper Jordan is speared from across a river near Mount Weather. A rescue party gets Jasper back to camp. Thelonious Jaha abstains from voting on the culling, postponing it for 10 days.

Sep. 16 - Trina and Pascal are killed by the Acid Fog overnight. Clarke comforts Charlotte after a nightmare.

Sep. 17 - Clarke tries to save Jasper. Another round of Acid Fog traps everyone overnight.

Sep. 18 - Clarke mercy-kills Atom after he was trapped in the Acid Fog.

Sep. 19 - Charlotte kills Wells at night.

Sep. 23 - Murphy is blamed for murdering Wells and they attempt to lynch him.

Sep. 24 - After a night on the run, Charlotte commits suicide. Murphy is banished. Raven Reyes leaves the Ark on a dropship headed to Earth. 320 Ark residents are culled to conserve oxygen. That night, flares are set off to alert the Ark they're alive on the ground. However, the flares burn down an entire village, presumably killing an unknown number of Grounders. Octavia is captured by Lincoln.

Sep. 25 - Overnight, Bellamy and a group of delinquents set out in search of a missing Octavia. That morning, John Mbege, Diggs, and Roma die at the hands of Grounders. The delinquents finally establish contact with the Ark just as a hurricane hits. Lincoln is captured and tortured.

Sep. 27 - Clarke and Bellamy head to find the bunker and discover guns. Almost everyone in camp eats hallucinogenic nuts. Dax is sent to kill Bellamy but Bellamy kills him instead. Bellamy is pardoned by Jaha. Octavia frees Lincoln.

Oct. 1 - The 100 and the Ark citizens celebrate Unity Day. Diana Sydney's Rebellion ends.

Oct. 2 - Clarke and Anya attempt a peace meeting at the bridge that ends in failure. The Exodus ship comes down a day early and crashes. The Woods Clan-Sky People Conflict officially begins

Oct. 5 - The delinquents investigate the wreckage of the Exodus ship. Murphy returns to the camp.

Oct. 6 - Clarke discovers Murphy was carrying hemorrhagic fever with him and he infects most of the Camp.

Oct. 7 - Raven and Jasper blow the bridge separating the Grounders from the Delinquents to delay the impending Grounder attack.

Oct. 9 - The delinquents' food is burned, prompting most of the campers to go on a hunting trip. Clarke and Finn are taken captive by the Grounders in order to save Tris after she was mortally injured in the bridge explosion. Tris dies and Clarke kills Caliban, trying to escape. Monty is taken by the Mountain Men.

Oct. 10 - Bellamy is taken hostage by Murphy, but later escapes. Clarke and Finn escape the Grounders with help from Lincoln.

Oct. 11 - The battle between the Delinquents and the Woods Clan occurs in the Delinquents Camp. The Ark disassembles into the original 12 Stations on the way down to Earth.

- Season 2 begins a day after season one and ends on November 3, 2149.

Oct. 12 - The next day, the surviving 48 of the 100 are taken by the Mountain Men to Mount Weather. Clarke breaks out of her quarantine room and is reunited with the other 47 Delinquents.

Oct. 13 - Octavia Blake meets Nyko. Lincoln and Nyko are captured by Reapers.

Oct. 14 - Indra, Octavia, and others free Nyko and other Grounders. Clarke and Anya escape Mount Weather. Kane gives Abby the Chancellor's pin.

Oct. 15 - Bellamy, Finn, Murphy, Monroe, and Sterling rescue Mel. Sterling dies in the process. Jaha meets a family of Nomadic Grounders in a desert but is later traded for a horse. Anya is killed by a Camp Jaha Guard. The guards bring Clarke into Camp Jaha thinking she is a Grounder.

Oct. 16 - Bellamy, Octavia, and Monroe bring Mel back to Camp Jaha. Kane is imprisoned in Tondc and reunites with Thelonious Jaha. Bellamy, Octavia, and Clarke leave Camp Jaha to go after Finn and Murphy.

Oct. 17 - Finn massacres 18 unarmed Grounders in Tondc.

Oct. 19 - Two days after the massacre, Finn is pardoned by the Council. Raven tells Clarke they need to blow Mount Weather's radio tower. Abby decides to join them.

Oct. 20 - A mission to Mount Weather takes place to destroy the radio tower at its summit. Bellamy and Octavia discover Lincoln as a Reaper. Thelonious Jaha is sent to Camp Jaha by the Commander.

Oct. 21 - Keenan Mykulak dies of prolonged radiation exposure. Bellamy and Octavia chain Lincoln up in the dropship. Lexa arrives.

Oct. 22 - Harper is taken by Lorelei Tsing and Cage and has her Bone Marrow extracted by Dr.Tsing. Clarke enters the Grounder's camp to negotiate a truce only to find out the only way to start a truce is for Finn to die. She then returns to Camp Jaha with the news.

Oct. 23 - Desperate attempts to keep Finn safe take place. That night, Clarke mercy-kills Finn.

Oct. 24 - A group travels to Tondc for Finn's funeral.

Oct. 25 - Finn's funeral takes place at Tondc, and his body is burnt. Gustus poisons himself to destroy the peace between the Sky People and the Woods Clan. Monty gets the radio signal out. Bellamy and Lincoln are sent to Mount Weather.

Oct. 26 - Bellamy and Lincoln travel to Mt. Weather. Clarke and Lexa avoid being killed by the Pauna. That night, Clarke gets an entourage and a horse. Indra makes Octavia her Second. Bellamy is taken into Mount Weather.

Oct. 27 - The Mountain Men attempt to assassinate Clarke and fail. Bellamy contacts Clarke from inside Mount Weather. Cage takes control of Mount Weather from his father. Clarke takes charge of the Sky People from her mother.

Oct. 29 - A meeting of the 12 Grounder Clans takes place in Tondc That night, a missile is sent directly from Mount Weather to Tondc, killing ~250 Grounders and Sky People.

Oct. 30 - The surviving residents are rescued from the bombing in Tondc. That night, they leave for Mount Weather. The Delinquents fight against the Mountain Men to save themselves. Some Mount Weather residents help the Delinquents hide from Cage.

Oct. 31 - That night, Lexa orders the death of Octavia as they wait for Bellamy to take out the Acid Fog machine.

Nov. 1 - The Battle of Mount Weather begins. The Acid Fog machine is destroyed. They march on Mount Weather. Philpott Dam is neutralized. That night, Lexa agrees to a truce with the Mountain Men in exchange for her people trapped inside Mount Weather. She places a kill order on Lincoln for refusing to leave.

Nov. 2 - Clarke, Bellamy, and Monty irradiate Level 5 of Mount Weather, killing every resident of said location except Carl Emerson. The Battle of Mount Weather ends as well as the Mount Weather War.

Nov. 3 - The Sky People return from Mount Weather to Camp Jaha. Clarke chooses not to enter Camp Jaha, and instead leaves on her own. Jaha meets A.L.I.E.

- Season 3 begins after a time skip on January 27, 2150.

Jan. 27 - Murphy is released from the lighthouse bunker after 86 days and travels with Jaha from the island back to the mainland. Unknown to Murphy, Jaha has A.L.I.E. with them. Jasper causes the death of 3 Ice Nation warriors. Clarke is captured by Roan. Bellamy, Monty, Kane, and Indra get trapped looking for Clarke.

Jan. 28 - Bellamy, Kane, Indra, and Monty encounter the survivors of Farm station, including Pike and Monty's mom, Hannah. Murphy leaves Jaha, Otan, and A.L.I.E. behind and takes off in a boat with Emori. Abby and Jackson save Nyko's life by using Mount Weather's medical facilities. Azgeda marches onto Trikru lands and Clarke is brought before Lexa by Roan.

Feb. 4 - A summit is held in Polis to join the Sky People into the Coalition as the thirteenth clan. The Ice Nation threatens the summit. The Ice Nation with help from Emerson sets the self-destruct code on Mount Weather and destroys it, killing 49 Sky People.

Feb. 5 - Nia challenges Lexa to a fight to the death. A memorial is held at Arkadia for those who died at Mount Weather. Pike, Bellamy, and others attempt to leave Arkadia to kill the Grounder peacekeeping army but are stopped and arrested. Roan, representing Nia, loses the fight to Lexa. However, Lexa spares his life, kills Nia, and makes Roan King of the Ice Nation.

Feb. 6 - Kane informs Pike that he was voted Chancellor. Pike, with nine others, murders the Grounder peacekeeping army as they sleep. Clarke and Lexa discover the murdered army. Jaha returns to Arkadia, with A.L.I.E. Clarke confronts Bellamy. He arrests her, but Octavia helps her escape. Lexa declares "Jus no drein jus daun." ("Blood must not have blood.")

Feb. 15 - Roan sends Emerson to Polis as a gift to Clarke. Clarke decides not to kill him and Lexa banishes him. Pike's men survey land near a Grounder village. That night they go to clear the village, but Octavia had warned them so the Grounders manage a surprise attack. Monroe is killed.

Feb. 16 - Lexa celebrates her Ascension Day. Semet interrupts to demand justice for his village. Lexa orders a blockade on Arkadia. Clarke goes to Lexa to say goodbye. They end up sleeping together. Titus accidentally kills Lexa.

Feb. 17 - The blockade on Arkadia goes into effect. Kane attempts a coup against Pike but is arrested by Bellamy and sentenced to death. Murphy and Clarke are released from Lexa's room. Bellamy tries to warn Octavia about Lincoln being sentenced, but she tases him and chains him in a cave instead.

Feb. 18 - Ontari kills the other Nightbloods overnight. Titus gives Clarke the Flame and kills himself. Clarke leaves Polis. Lincoln gives himself up to allow the others to escape. Kane and the rest of the resistance escape, while Lincoln is executed by Pike.

Feb. 19 - The resistance arrives in the cave, where Octavia beats up Bellamy. Pike is captured and delivered to the Grounders. A.L.I.E. uses Raven to get Abby to take the chip. Arkadia is taken over by A.L.I.E. Jasper escapes with Raven and runs into Clarke who arrives in Arkadia. That night, they go to Niylah's trade-post and they manage to un-chip Raven.

Feb. 21 - The resistance (minus Harper, Miller, and Bryan) heads back to Arkadia which is now abandoned. Emori arrives in Polis, and is now chipped. Emerson takes Harper, Miller, and Bryan and kills Sinclair. Clarke kills Emerson. That night they burn Lincoln and Sinclair's bodies. Bellamy, Clarke, Octavia, and Jasper set out to go find Luna.

Feb. 22 - Ontari is now chipped and A.L.I.E. is taking control over Polis. Bellamy, Clarke, Octavia, and Jasper find a way to signal Luna, and get sedated. Kane caves and takes the chip.

Feb. 23 - Clarke and the others discover that they are on the Floukru oil rig and later ask Luna to help them, to which she refuses due to being a strict pacifist. Some of A.L.I.E.'s followers find their way to the oil rig and begin to torture its citizens, including Luna. Jasper is chipped. Clarke and co. are once again made unconscious and are sent back to dry land.

Feb. 24 - Jasper reveals to the group that he is chipped and part of A.L.I.E.'s army. One of A.L.I.E.'s followers attempts to murder Clarke but is killed by Roan. Roan joins the resistance movement against the AI. They hatch a plan to get into Polis. Jaha strikes Ontari on the side of the head, making her brain dead. The battles in Polis and the City of Light take place concurrently. A.L.I.E. is destroyed, ending the War Against A.L.I.E. Octavia kills Pike.

- Season 4 begins right after season three ends, Feb 24, 2150.

Feb. 24 - Sky People and Grounders deal with the repercussions of A.L.I.E. and the City of Light. Azgeda, led by Echo, takes over Polis. Bellamy tries to bargain with Echo, while Abby and Clarke try to save Roan's life. All of the Sky People left in Polis are taken prisoner.

Feb. 25 - Echo advises Roan to kill Clarke. Clarke convinces Roan to make Skaikru the 13th Clan in exchange for the Flame. Roan announces that Azgeda will honor Lexa's Coalition. The radiation wave hits Egypt.

Mar. 5 - In Arkadia, Clarke, Bellamy, Raven, and Monty brainstorm a solution to the radiation problem. Bellamy, Monty, Miller, Bryan, and Harper set out for Farm Station to get a hydro-generator. At Farm Station, they find a group of slaves – to free them, they blow up the hydro-generator. Meanwhile, in Polis, Kane and Octavia are unsuccessful in convincing the Trishanakru ambassador, Rafel, not to challenge Roan. Echo and Abby are also unsuccessful in convincing the injured Roan to delay the ambassador meeting. In the evening, Octavia kills Rafel.

Mar. 6 - The ambassadors meet and Roan announces that Rafel was found dead. Bellamy's group returns to Arkadia with the slaves but lacking the hydro-generator.

Mar. 13 - The sick Floukru members with Acute Radiation Syndrome (ARS) arrive in Arkadia. All of the Floukru died from ARS, leaving Luna the only survivor. Jaha, Clarke and Bellamy are on the search to find the Second Dawn Bunker, but their attempts failed. Clarke writes down a list of a hundred people who get to live. The Sky People discover that Luna is immune to radiation due to her Nightblood.

Mar. 18 - Abby's group arrives on Becca's Island. Nyko is killed by one of the drones. Abby's group found Becca's Lab in the middle of the island. The Sky People discover Clarke's list and confront her, but Jaha manages to settle the tensions. Roan declares war on both Skaikru and Trikru, leaving Kane and Bellamy as hostages. Octavia escapes Polis in order to warn her people. She gets stabbed by Echo and falls off a cliff, but she survives.

Mar. 19 - Ilian saves Octavia and brings her to Arkadia, where she manages to warn her people about Azgeda. As the Ice Nation marches to Arkadia, the Sky People surround them and Clarke negotiates with Roan. A deal is finally made. Ilian burns down Alpha Station. On Becca's Island, Raven discovers that she has intelligence due to A.L.I.E. and the EMP.

Mar. 20 - An angry mob of Sky People attempts to kill Ilian for burning down Alpha Station, but Kane threatens to shoot them if they harm him. Roan, Clarke, and Bellamy are delivering hydrazine, but one of them gets emptied after one barrel was pierced by an arrow during the Trikru attack. Octavia attempts to kill Ilian, but can't do it. Clarke arrives on Becca's Island. Black Rain hits Arkadia and 18 Sky People die. At Becca's mansion, a scavenger attempts to kill Emori, but is captured. After Emori claims that this was the man who did terrible things to her and her brother, Otan, Clarke decides to experiment on the scavenger.

Mar. 21 - The scavenger dies in the radiation experiment. Clarke discovers that Emori lied about the scavenger and attempts to test the experiment on Emori as punishment. Murphy refuses, forcing Clarke to inject herself with Nightblood instead. Abby destroys the radiation test chamber. Jaha discovers that the Second Dawn Bunker is in Polis and finds it successfully.

Mar. 25 - Jaha makes an announcement about the Second Dawn Bunker. The Sky People decide to leave Arkadia and head to the bunker. Trikru attempts to assassinate Roan, but fails.

Mar. 26 - Jasper, Riley, Harper, and some of the other Sky People decide to stay behind at Arkadia. Monty decides to stay with them in case they change their minds.

Mar. 28 - The Final Conclave begins at Polis. Roan discovers that Echo is trying to cheat and banishes her from Azgeda. Roan and Luna are killed in the battle. Octavia wins the Conclave, but decides that all of the clans share the bunker equally.

Mar. 29 - Jasper, Riley, and some of the other Sky People at Arkadia, commit suicide. Monty and Harper leave Arkadia to find the rest of their friends.

Mar. 30 - The Second Culling takes place at the Second Dawn bunker. Sergeant Miller gives up his spot for his son. Monty and Harper reunite with Bellamy and Clarke's group. Group led by Bellamy and Clarke make their way to Becca's island.

Mar. 31 - Praimfaya destroys Polis. Clarke sacrifices herself to help her friends escape Praimfaya. Bellamy Blake, Raven Reyes, Monty Green, Harper McIntyre, John Murphy, Emori, and Echo escape in a rocket to the Go-Sci Ring. Praimfaya renders Earth uninhabitable.

- Season 5 begins after a time jump of six years and seven days later. PAY ATTENTION TO THE YEARS. 

May 12 - 42 days after Praimfaya, Clarke emerges from the ground and heads to Polis.

May 16 - Clarke arrives at the ruins of Polis. She tries to dig to the bunker but is unable to reach it. She later heads to the ruins of Arkadia but is unable to find food or water. In the bunker, Octavia joins the delegates in an assembly where she resolves a feud between two different clans. They hear Clarke's digging, so Marcus and Abigail put on their suits and try to get to her, but the door doesn't open due to the Polis tower collapsing on top of the bunker. The overpopulation of the bunker will inhibit them from surviving for longer than five years. Kara Cooper stages a coup with her fellow Skaikru to take the food supply for themselves. Octavia, along with the help of Jaha, manages to open the door to the farm and stop the coup. Jaha dies of blood loss. For the guilty, their punishment is to fight to the death to earn their freedom like gladiators.

? - Clarke goes out searching for resources but eventually ends up exhausted in a desert. She almost gives up. Following a bird, she finds a green valley.

May 28 - 58 days after Praimfaya, Clarke is staying within a village in the valley when she encounters a Nightblood child named Madi.

2152 - Two years after Praimfaya, the "Dark Year" occurs in the Second Dawn Bunker, when Wonkru is forced to cannibalize those who died in the fighting pits.

Apr. 7 - 6 years and 7 days after Praimfaya, Bellamy's group is continuing to try to figure out how to descend back to Earth. Murphy notices something new in Earth's orbit: the Eligius IV. A couple hours later, the group watches the Gagarin descent from Eligius IV towards Earth. On the ground, Clarke and Madi witness the Gagarin land. After ordering Madi to hide, Clarke watches the Gagarin passengers explore the ground. A couple of them find Madi. Clarke and Madi kill the two, but the gunshots give away to the Gagarin passengers that they are not alone.

Apr. 9 - 2,201 days after Praimfaya, Bellamy's group heads to the Eligius IV to get hydrazine fuel. There, they found out that the passengers onboard are prisoners. One of them wakes up from cryosleep and attacks them, only to be killed by Bellamy and Echo. Raven and Murphy stay behind to guard the prisoners, who are in cryo-sleep, while Bellamy's group finally goes back to the ground. On the ground, Clarke and Madi escape from the prisoners after killing two more of them. Clarke gets re-captured by the prisoners, led by Charmaine Diyoza. Diyoza interrogates Clarke. After arriving on the ground, Bellamy's group is held at gunpoint by two prisoners, but Madi saves Bellamy's group and kills two prisoners. Later, after the prisoners tortures Clarke, Bellamy intervenes and makes a deal with Diyoza to spare Clarke's life or else all the 283 prisoners in the ship would die.

In the bunker, Kane prepares to fight against others for his freedom in the gladiator ring, but after killing his opponents, he is forced to fight again tomorrow.

Apr. 10 - Bellamy negotiates with the prisoners in order to get them to open the bunker. Clarke and Bellamy open the bunker with help from the prisoners. They manage to help many people be released from the bunker. Diyoza and the prisoners betray Wonkru, and open the Cryo-pods back on Eligius IV, releasing all the prisoners on board. The prisoners hold Kane and Abby hostage as they escape back to Eligius IV and Shallow Valley. Enraged, Octavia declares war on Diyoza and the prisoners.

Apr. 11 - Against Clarke's advice, Octavia leads her people towards Shallow Valley, along with Bellamy and Clarke. Meanwhile, at Shallow Valley, Diyoza forces Abby and Kane to help some of the sick prisoners. Murphy escapes with the help of Miles Shaw, while Raven stays behind. Later, Murphy reunites with his friends at Shallow Valley, but due to the shock collar around his neck, Murphy and Emori decide to stay behind. Diyoza, Shaw, and Paxton McCreary fly on the Gagarin and fire a missile at the Wonkru camp. In the desert, twelve of the Wonkru members die, due to one being killed by parasitic worms and eleven being killed by the glass-sharped sandstorm.

Apr. 12 - The next morning, Octavia decides to retreat. Then, Madi and the group arrive. Madi reunites with Clarke, and Bellamy reunites with Echo, whom Octavia is unhappy to see. Later, in Polis, Octavia threatens to banish Echo again for her past actions. However, Octavia makes a deal with Echo and her friends to allow Echo to infiltrate Diyoza's ship to get access to the ship's computer, in order to lift up her banishment. Murphy and Emori kill two prisoners and capture McCreary. Some of the Wonkru members defect to the Gagarin, along with Echo, but Cooper shoots at the defectors, while the remaining defectors arrive at the ship, but are put into shock collars. Madi comes to Octavia, revealing to her that she is in fact, born a true Nightblood. Madi becomes part of Wonkru.

Apr. 13 - The next day, Diyoza welcomes the defectors into the village in Shallow Valley. Madi begins to take Wonkru classes in Polis. Clarke and the others discover that Octavia and Cooper are breeding the parasitic worms to use as weapons against Diyoza and the prisoners. Clarke and the others later confront her. Echo exposes Shaw's treachery to Diyoza, in order to open a backdoor to the ship's computers. In Polis, Clarke and the others access the ship's computer systems.

Apr. 14 - In Shallow Valley, Abby discovers that Diyoza is pregnant. A badly-beaten Shaw is put in the shock collar and is held with other defectors for his treachery. In Polis, Clarke has a plan to sabotage Wonkru's plan for war by using the worms to kill Cooper to make it look like an accident, to allow Indra to kill the worms. Meanwhile, Abby manages to give successful medical treatment to the prisoners. After Murphy reveals to McCreary that Diyoza didn't trade Raven for him and left him to die, McCreary decides to help Murphy and Emori get Raven back, and brings them to the village as captives. Octavia has Clarke arrested for murder and sentences her to death. Bellamy puts Octavia in a coma to prevent her from killing Clarke and sending the worms' eggs to Shallow Valley.

Apr. 15 - In Shallow Valley, Echo, Emori, Raven, and Murphy devise a plan to cause a fight between Diyoza and McCreary's group and escape with the defectors. Back in Polis, with Octavia in a coma, Indra announces to Wonkru that Octavia is sick and plans to lead them to Shallow Valley peacefully without war, but Miller opposes this, saying that Wonkru should follow Octavia's plan to march for war. Due to this, Bellamy and Indra plan to make Madi a new Commander, which Clarke opposes.

Meanwhile, in the Valley, Murphy reveals to McCreary that a medical treatment helped cure Diyoza's people, causing McCreary and his group to go against Diyoza's leadership. Later at night, as McCreary and his people confront Diyoza and her group, Murphy causes a fight between two groups of prisoners. Raven, Murphy, Echo, Emori, and the defectors escape with Kane, Shaw, and Diyoza, while McCreary and his people take control, with Abby being held as hostage.

As the Ascension ceremony begins in Polis, Clarke escapes from her chains, with the help from Niylah. Meanwhile, during the Ascension ceremony, Madi is implanted with the Flame. Clarke tries to kill Octavia, but Octavia convinces Clarke that she will help her stop the Ascension. Later, Octavia has Gaia, Indra, and Bellamy arrested.

Apr. 16 - The next morning, in Shallow Valley, with McCreary and his group in control, he announces that he will kill their enemies and cure his people.

In Polis, Clarke and Madi escape to the Valley, unaware that McCreary has taken control. Meanwhile, Octavia sentences Gaia, Indra, and Bellamy to fight in the arena. As she enters the room, she sheds a tear.

Apr. 17 - In Polis, at the Second Dawn Bunker, Monty shows Octavia how the plants and algae work in the hydrofarm. While in the Rover, Madi discovers what happened to Becca in her flashbacks through the Flame.

Apr. 18 - Clarke and Madi arrive in Shallow Valley and find Abby unconscious. While helping her, they are discovered by McCreary and his men. McCreary threatens Clarke to help cure his group.

In the Second Dawn Bunker, Gaia, Indra, and Bellamy fight in the arena. Monty and Harper interrupt and show Wonkru that the hydrofarm is working again. Wonkru begins to rebel against Octavia and she burns down the hydrofarm. Afterward, Octavia leads Wonkru as they began to march towards the valley.

Apr. 19 - As Wonkru marches in the desert, Bellamy is radioed by Echo, who warns him that McCreary and his men know Wonkru is coming to the Valley. Clarke and Madi manage to save Abby.

Apr. 20 - A heartbroken Abby reveals to Clarke that she was responsible for the Dark Year and Octavia's dark nature. Diyoza and Kane turn themselves in to McCreary and make a deal with him.

Apr. 25 - Wonkru is ambushed and attacked by McCreary's group. Clarke betrays Raven, Echo, and Shaw. After Echo and Madi convince her to overcome her terrible decisions, Clarke, with a change of heart, rescues them. Murphy, Emori, Echo, and Madi rescue Indra, Gaia, Bellamy, and Octavia, who also have a change of heart.

Apr. 26 - McCreary is killed and the prisoners surrender to Wonkru. Before dying, McCreary initiates the Damocles Event, thus destroying Shallow Valley. The remaining human race goes to space due to Earth's destruction and is put in cryosleep on Eligius IV. Earth is expected to take at least ten years to recover enough to be habitable again.

Apr. 26, 2157 - 1-year anniversary of the long nap. Monty records his first message for Clarke and Bellamy.

Mar. 10, 2158 - 2 years after everyone was put in cryosleep, Monty and Harper announce her pregnancy.

May 10, 2158 - 2.5 years after everyone was put in cryosleep, Monty and Harper present their newborn child named Jordan.

Apr. 26, 2166 - 10-year anniversary of the long nap. Monty says that he will not wake anyone since the Earth is still unsuitable for life.

Nov. 3, 2184 - 28 years after everyone was put in cryosleep, Monty and Harper put Jordan into cryosleep (making him 26). Also, they tell that Earth isn't coming back and Monty starts working on a plan "B".

Feb. 8, 2206 - 50 years after everyone was put in cryosleep, Harper dies due to sickness caused by her Dad's genetic condition. Monty cracks the Eligius III mission files and sets the coordinates on Eligius IV to fly to a new habitable world located in the Goldilocks Zone of a binary system. Monty estimates the travel taking 75 years.

Apr. 26, 2281 - 125 years after everyone was put in cryosleep, Jordan wakes Clarke and Bellamy up and tells them about himself and shows them Monty's videos. Eligius IV arrives in a new world.

- Season 6 begins on the same day that season 5 ended. It ends on May 6. Again, pay attention to the years!

2181 - Russell Lightbourne and the other Primes try to do bone marrow transplantation to recreate Nightblood, but it fails, due to not knowing the formula.

2211 - Gabriel Santiago defects from Sanctum with the help from Ryker Desai, and later founds the Children of Gabriel.

2260 - Delilah Workman is born.

2270 - Tai and Arabel's infant son is sacrificed in the Offering Grove. Josephine VII murders Isaac.

2271 - Gabriel Santiago's host dies and Eduardo resurrects him in Xavier. Gabriel kills Eduardo and takes Xavier's identity. Devastated by the loss of her infant son, Arabel lies down in the Offering Grove, committing suicide.

2274 - Rose is born.

2275 - Josephine's VII host is thrown out of the window by Kaylee.

2281 - Clarke, Bellamy, and Jordan wake up the rest of the team and they explore the world together, starting with landing on the site Alpha. The group lands on Alpha, a habitable moon. During the night, they are attacked by a swarm of bugs, which causes them to run towards the beacon, located inside a radiation defense perimeter. Because of the lack of knowledge, Miles Shaw runs into it and dies.

Apr. 27 - On the next day, the group discovers a settlement on Alpha. During the exploration of the settlement, each member of the group slowly starts to go insane and hurt each other due to the Red Sun Eclipse.

Meanwhile, the mothership is hijacked by a team of four people. However, with the help of Raven, Diyoza, and Madi, the ship is taken back. The second group descends on the moon and reunites with the first group. After being reunited, the group meets the actual inhabitants of Sanctum and their leader, Russell Lightbourne.

Apr. 28 - While Clarke is trying to bargain for her people to stay, Bellamy, Echo, Octavia, and Raven are returning back to the dropship to move it closer to the settlement while they encounter another group called the Children of Gabriel. Clarke helps to save one of the important citizens of Sanctum and earns the right to stay for her group.

Apr. 29 - On Naming Day, Priya is "reincarnated" in Delilah Workman's body, making her "Priya VII." Josephine Lightbourne is also "reincarnated" in Clarke's body. Octavia is held captive by the Children of Gabriel but escapes with Rose. Later, they're saved by Diyoza and Jade, but Rose gets shot by a member of the Children of Gabriel.

Apr. 30 - Jordan, Bellamy, Murphy, and Gaia discover a dark secret that the ruling family of Sanctum, known as the Primes: they are using the bodies of the Nightblood hosts for "reincarnation" purposes to keep them immortal and to stay in power. After spying on the group, Josephine, who is inside Clarke's body, convinces Murphy to work with her by offering him immortality.

May 1 - While looking for a cure to help Octavia, "Xavier" reveals to Diyoza about the Children of Gabriel. In Sanctum, Gaia begins a Separation Ritual to help Madi stop Sheidheda, the Dark Commander. Abby and Raven fly on the Gagarin to the mothership. Bellamy tries to kill Russell for what he did to Clarke, but can't do it. Meanwhile, Diyoza, Octavia, and "Xavier" discover a message from the Anomaly. Echo learns of Clarke's supposed death and Bellamy decides not to go to war against the Primes. Angry at Clarke's supposed death, Madi banishes Gaia.

After Josephine falls asleep, it allows Clarke to wake up in her mind space. Josephine appears there and explains that 2 minds in one body are killing the host and it won't last long, so Clarke has to give up and make a sacrifice to save her people. Josephine succeeds and Clarke shows her how to erase her mind.

May 2 - In the morning, Bellamy and Miller are talking to Russell about the compound, when Josephine walks in to say to her father that she knows how to get rid of Clarke. However, in Clarke's body, a projection of Monty Green shows up to Clarke and convinces her to overcome her demons to stop the Primes. They break into Josephine's mind space and manage to send a message to Bellamy using the Morse code, revealing to him that Clarke is alive. Bellamy reveals to others that Clarke is alive.

Meanwhile, in the forest, Diyoza and Octavia discover that Xavier is actually Gabriel Santiago.

Madi assassinates Miranda Mason and gets locked up with the others, while Bellamy escapes with a captive Josephine.

On Eligius IV, Marcus Kane is resurrected, only to be horrified that he was put into a new body of a new Host.

Meanwhile, after arriving outside near the Anomaly, Diyoza disappears and Octavia gets healed.

May 3 - Bellamy continues to seek out Josephine to the Children of Gabriel. They meet and get them captured in the caves. During their confrontations, the Children of Gabriel realize that Josephine is one of the Primes and prepare to cut off her head, however she gives control to Clarke to save them both. Clarke successfully escapes and goes to Gabriel.

At the Verge, Gabriel brings Octavia back to the camp and asks her about the Anomaly. Octavia goes through her memories and seeks redemption there. She wakes up with the will to save her friends, but gets interrupted by Clarke's message.

Meanwhile on the mothership, Kane does not approve of Abby's decision in bringing him back in a different body. With help of Indra and Raven, they steal the Nightblood serum from Simone, and Marcus kills himself for the better good.

Simone is assassinated.

Gabriel, Octavia, and Bellamy manage to save Clarke, who also defeats Josephine.

Gaia and Echo launch a plan to stop the Primes.

Ryker Desai betrays Echo.

Russell sentences Clarke's friends to death, but they're spared in order for them to make more Nightblood.

May 4 - Octavia, Bellamy, Clarke, and Gabriel discuss a plan for overthrowing Primes and taking over Sanctum using the toxin bomb for distraction. The Children of Gabriel meet them and one of their members threatens Gabriel for betrayal. Octavia and Bellamy go into the caves to collect more toxins for the bomb.

Meanwhile in Sanctum, Russell prepares to test the first produced Nightblood serum on Echo in order to resurrect Simone. He also makes a deal with Murphy to bring back Josephine in exchange for immortality. Ryker makes Echo a Nightblood but fails to kill her due to being interrupted by Gaia and Nate and gets killed by Echo instead.

By the night, Murphy succeeds with his mission but this time it's Clarke pretending to be Josephine.

May 5 - Russell continues using Madi to produce more Nightblood. He gives Murphy and Emori mind drives, making them Nightbloods. He also kills Abby and 3 of his guards so they could become hosts for other Primes.

Clarke succeeds in rescuing her friends and with help of Priya and lowers the shield so Bellamy, Octavia, and Children of Gabriel can attack Sanctum. They spread the truth about Primes, forcing Russell to release Red Sun Toxin, causing chaos and insanity of citizens, and run away to the mothership with his family.

Wonkru and the Primes fight for control of the mothership, until it is taken back by Wonkru.

Clarke's friends manage to remove Sheidheda from Madi, who reunites with Clarke.

In Sanctum, Bellamy and the others fight and knock out all of the citizens.

May 6 - Russell is apprehended for his crimes.

Clarke and the other Wonkru members arrive back at Sanctum.

Gabriel, Bellamy, Octavia, and Echo begin investigating the Anomaly. Gabriel shows them an extraterrestrial artifact known as the Anomaly Stone, and they begin to activate it. Hope Diyoza emerges from the Anomaly and Octavia vanishes.

- Season 7 begins the same day season 6 ended. 

It's very difficult to put this in order due to all of the time and location jumps. I would recommend looking at the timeline for season 7 on The 100 Wiki because it is listed by location, making it much easier to read. I'll post the link both here and in the comments, or you can just look up "The 100 Timeline" and then select "season 7" once you scroll. You can then look at the different planets.

https://the100.fandom.com/wiki/Timeline#Earth