A little bit of luck and some hearty genes... The 100's Grounders are a hardy bunch, but just how did they manage to survive a nuclear apocalypse that wiped out the majority of the human race? 'The 100' Season 3: Prepare For '16 Episodes Of Pain', Jason Rothenberg Teases Extended Run It's a question that has plagued The 100's viewers for two seasons now, and the writers have recently shed a little light on the origins of Lexa and Lincoln's people.
