In season 3, the survivors of The Ark, dubbed Skaikru, were systematically taken over by an artificial intelligence called A.L.I.E. who manipulated their actions while storing their conscious minds in The City of Light.
The descendants of those who survived the destruction on Earth grew up on a space station called The Ark, with limited resources and death as the punishment for even the most petty of crimes.
In the end, Clarke chose free will and shut A.L.I.E. down, bringing everyone’s consciousness back to their bodies.
The characters on The 100 have faced some extreme challenges.