Killer Asteroid

S1, E1: 65 Million Years ago, an asteroid impact caused a cascade of catastrophes that led to the downfall of the dinosaurs, but what would happen if the same size space rock struck near the same spot again? How would modern humans cope with a hailstorm of falling rocks and debris, mega tsunamis, out-of-control fires, blast-furnace temperatures, and a destroyed ozone layer? In the wake of worldwide destruction, who would survive...and who would perish?