Almost 13,000 years ago, North America underwent drastic changes at a rapid rate. Mammoths, mastodons, giant ground sloths, and many other large animals went extinct. Around the same time, the Clovis ...

New evidence suggests that a comet explosion over North America may have triggered a massive wave of destruction nearly 13,000 years ago, killing off mammoths and mastodons and wiping out one of the ...