For as long as humans have sailed the seas, they have feared the deadly predators lurking just beneath the waves. But what if the most terrifying monster wasn’t a known species, but an ancient ghost of impossible size, a creature science says has been extinct for millions of years?

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Learn more about your ad choices. Visit megaphone.fm/adchoices