Historically, there have been four oceans: the Atlantic, Pacific, Indian, and Arctic. On Feb. 9, U.S. Secretary of the Interior Doug Burgum announced the Gulf of Mexico had officially been changed to ...

The world still holds mysteries, even the size of continents. And sometimes, the greatest discoveries are the ones we were never quite sure existed.

If Iceland is part of a submerged continent, Earth’s continental map may need a dramatic update—potentially changing science textbooks forever. Where is Athena? A mysterious private moon ...