It’s often said that we know less about what is hiding in Earth’s oceans than we do about what lurks in the depths of space. While that might be hyperbole, a new discovery off the coast of Australia certainly lends weight to the argument.

Hidden some 2,000 meters beneath the waves off the east coast of Australia, researchers stumbled upon something they didn’t even know was there: a massive volcano graveyard that they are calling the “Lost World” of extinct underwater volcanos.