What's at the bottom of the Mariana Trench, and how do we know? How deep does the ocean go? We'll answer these questions and more in this deep dive into the world's oceans. Come on in: The water's ...

Bizarre creatures like vampire squid and blobfish make their home in the dark, cold, depths of the deep sea, but most of this watery realm remains a complete mystery. That's because humans have seen ...