History Series / The100

* AsskickingEqualsAuthority:

* NuclearNasty: One of the threats of a post-nuclear-apocalypse Earth. The first animal seen is a beautiful buck grazing in the forest-and then it turns and we see it has part of a second head growing out of its first. Mutant humans are also present, often with physical deformations such as extreme syndactyly or a deformed mouth or hand.

* ConLang: Trigedasleng, the [[EternalEnglish other]] language spoken by the Grounders, which seems to be at least partially based on English. The creator of the language says that it is derived from English, specifically from codes used by survivors to identify if someone was friend or foe. If you understood the words you were presumably a member of the group; it then developed into a language of its own with distinct rules.

** By the end of Season 4, the StatusQuo of the first three seasons is broken completely. [[spoiler:Due to the Praimfaya wave all remaining twelve clans are forced to become one (called Wonkru) and 100 survivors from each clan band together to survive the radiation. Not only does this remove all of the individual clans from the equation but for the first time in Grounder culture the leader of their new people is no longer a Nightblood but instead a former member of Skaikru Octavia. Indra even {{lampshade}}s this noting that the time of the Commanders has passed.]]

** "Perverse Instantiation, Part 2": It is revealed by ALIE that [[spoiler: the nuclear plants are going to meltdown in 6 months and kill all life on earth even the people who are immune to radiation]]. She saw putting people in the City of Light as a way of trying to save humanity. Also, Octavia [[spoiler: kills Pike.]]

* MohsScaleOfScienceFictionHardness: The show started off pretty far on [[Mohs/SpeculativeScience the hard end of the scale]], but each season introduces new, more implausible elements than the season before it, till by Season 6 they're on another planet full of alien life and [[NegativeSpaceWedgie "temporal anomalies"]].
** Gets kind of weird when you remember that the Ark space station from Season 1 and the Eligius spaceship from Season 5 were built around the same time, but while the Ark's only a little beyond what current space programs can produce (its main advances being its size, its self-sufficiency, and CentrifugalGravity), Eligius can travel to other solar systems (albeit at slower-than-light speeds), has [[HumanPopsicle suspended animation pods]], ArtificialGravity from some unknown but definitely ''non''-centrifugal source, and a dropship that can land on Earth and return to orbit multiple times, with no apparent need to refuel.

** Season 6: [[spoiler:Shaw, Kane, Abby, Josephine and Simone.]]
** Season 7: [[spoiler:Bellamy, Gabriel, Diyoza, Sheidheda, Cadogan, Russell, Nelson, Hatch, Orlando and Doucette.]]

*** Lincoln's village was built around the Lincoln memorial.
*** Lexa was named after Alexandria, VA which is located on the other side of the Potomac River from D.C.
*** Costia, Lexa's former lover, is derived from Anacostia, either the neighborhood in Washington D.C. or the river.
*** Other Trikru members include Tomac (after the Potomac River), Delano (after the Franklin Delano Roosevelt Memorial in Washington), and Penn (after Pennsylvania Avenue).

*** Queen Nia of the Ice Nation is named after Niagra Falls which is in the Ice Nation's territory.
*** Ontari is short for Ontario.

*** Lexa is likely short for Alexandria, a Virginian city on the other side of the Potomac River from Washington D.C.

** Grounders have historically themed names.
*** Lincoln's village was built around the Lincoln memorial.
*** Lexa is a name derived from Alexander.
*** Gustus is also a derivative of Augustus.
*** Octavia's eligibility for both the historical and sci-fi name themes is a nod to her dabbling in both cultures.

In October 2019, it was reported that The CW is developing a prequel spin-off set 97 years before the start of the series. The cast was announced in February 2020, with the [[PoorlyDisguisedPilot backdoor pilot]] being aired as part of ''The 100'''s final season on July 8, 2020.

** [[spoiler:Octavia and Diyoza also bond to some degree in Season 6, after admitting to being NotSoDifferent and both had been exiled from Sanctum. Then in season 7 they become HeterosexualLifePartners and raise Hope together.]]

* NotSoDifferent:
** Clarke and Bellamy come from wildly different backgrounds: she's the only child of influential parents and grew up relatively privileged, while he and his mother (who weren't that well-off to begin with) had to hide his illegal half-sister her whole life. As a result of their backstories, Clarke respects authority while Bellamy resents it. However, they are both good leaders who are devoted to their people and have to make tough choices in order to survive, and for this reason their initial TeethClenchedTeamwork gives way to a more genuine partnership.

** Foreshadowed and implied throughout the beginning of Season 3, "Thirteen" reveals that the Grounders and the Sky Crew have a historical connection leading back the formation of the Ark and the First Commander.
* NotSoSimilar: After Bellamy motivates the 100 in the face of a Grounder attack by explaining [[NotSoDifferent that after learning to fight and survive they are Grounders as well]], Clarke steps forward and says that they are ''not'' Grounders. She does not want them to descend to savagery in the name of self-defense and she was attempting to convince them to try and seek shelter with Luna's clan instead of fighting in a battle that they could possibly lose.

** [[spoiler:Octavia and Diyoza also bond to some degree in Season 6, after admitting to being NotSoDifferent and both had been exiled from Sanctum.]]

** Octavia starts off as innocent and trusting, but by Season 5 she is a tyrannical despot styled after the Red Queen from Alice in Wonderland.

** [[spoiler:Happens again after the Praimfaya wave devastates most of the planet and kills most of the remaining life. Clarke and Madi wander this environment for six years. Only a single valley is left untouched, and ''that'' gets destroyed when McCreary activates Damocles.]]

The series premiered in the United States on March 19, 2014 and its first five seasons can currently be streamed on Creator/{{Netflix}}. It finished its run on September 30, 2020, after seven seasons and (aptly enough) 100 episodes.

* ArcNumber: [[TitleByNumber 100]]. It's the number of delinquents originally planned to be sent down to earth, the number of slots left [[spoiler:in Arkadia in Season 4, and the number of representatives each clan gets to send to the bunker.]]

* DrivenToSuicide: Pre-teen Charlotte (the youngest of the young convicts sent to Earth), guilt-ridden over having killed Wells in a misguided attempt to quiet her inner demons and unwilling to be the cause of any more bloodletting, averts InfantImmortality by jumping off a cliff to her death.

* HonorBeforeReason: Particularly in seasons 1 and 2, Grounder characters' decisionmaking frequently goes against their own best interests because of their often blind adherence to tradition, extreme hostility to outsiders, and resistance to change.

One hundred juvenile delinquents are sent down to Earth in a dropship to see if it is survivable. Cut off from the Ark due to a landing mishap, the delinquents try to set up camp on the ground. But while the group's eventual leaders -- Clarke Griffin (Creator/ElizaTaylor), a privileged young woman who was kept in solitary lockup because of the secret her father was killed for knowing, and Bellamy Blake (Creator/BobMorley), a rebellious former guard demoted after the Ark learned about his illegal younger sister Octavia (Creator/MarieAvgeropoulos) -- find that establishing a functional society comprised of teenagers on an unfamiliar planet is hard enough by itself, there's one other major complication: they aren't the only humans on Earth. The camp quickly comes into conflict with the Grounders, clans of people who also survived the apocalypse, and who aren't happy about the 100 crashlanding onto their territory.

** [[spoiler:Happens again after the Praimfaya wave devastates most of the planet and kills most of the remaining life. Clarke and Madi wander this environment for six years.]]

* OnlyChildSyndrome:
** Justified in the case of the Sky People: Bellamy and Octavia are the only siblings from the Ark, and their being siblings is given special weight considering [[PopulationControl no one on the Ark is allowed to have more than one kid]].
** Played straight as the setting expands. None of the Grounders or Sanctum residents are shown to have siblings. The harsh environment may have something to do with it.

The series premiered in the United States on March 19, 2014. Its first five seasons can currently be streamed on Creator/{{Netflix}}, its sixth season premiered in April 2019, and it has been renewed for a seventh and final season.

* SequelEscalation: The stakes get higher with every season. While Season 1 focuses on the delinquents dealing with a few Trikru authorities, Season 3 features an interclan war, and Season 4 is about the cast trying to survive ''yet another apocalypse''.

* HatePlague: On Sanctum, the eclipse of the two suns causes plants to release a chemical that turns any animal who breathes it (humans included) insanely delusional and violent. Everyone is affected differently, with most people trying to hurt each other: Emori tries to murder everyone, Echo is in so much pain she sedates herself, Bellamy becomes so paranoid he wants to kill Clarke, Nathan and Eric both believe that bugs are trying to eat Nathan resulting in Eric attacking Nathan in the belief he is saving him, Clarke thinks her mother is telling her to kill herself, and Murphy is totally unaffected.

* HatePlague: On Sanctum, the eclipse of the two suns causes plants to release a chemical that turns any animal who breathes it (humans included) insanely delusional and violent. Oddly, while everyone else affected by it takes their violence out on others, Clarke's delusions keep trying to get her to kill ''herself''.

** The Grounder society is so wound up in combat that they only acknowledge an end to fighting when somebody dies: Their death prayer/blessing is "[[PeacefulInDeath Your fight is over]]". Clarke's use of the phrase is a show of respect and is one of the first things to get Lexa's notice that she is more than just a 'normal' member of Sky Crew.