NOVA/WGBH

What killed the mammoths? Near the end of the last ice age 13,000 years ago, these mighty beasts disappeared from North America together with some 35 other groups of mammals. For four decades, debate has raged over the cause of their abrupt demise. NOVA presents an in-depth investigation of a controversial new hypothesis which suggests that a massive impact from space could be the culprit, and also explores alternate theories.