Mysterious deep-sea ‘Bloop’ had scientists convinced they’d finally found the giant Megalodon

A mysterious underwater noise recorded in 1997, the “Bloop,” fuelled years of speculation about megalodon and other undiscovered giants. But NOAA’s long-running investigation eventually traced the sound to Antarctic icequakes, not a living creature. The finding reveals less about ancient sharks and more about a warming planet, whose shifting ice now produces noises once mistaken for monsters.