Editor’s note: Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Just as Earth’s land surface has ...

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 ...

Hadal trenches, with their deepest locations situated in the so-called hadal zone, the deepest parts of the ocean in water depth >6km, are the least-explored environment on Earth, linking the Earth's ...