In the mid-20th century, when people looked at a map of the world, they saw the familiar continents surrounded by vast, ...

There's the Pacific, the Atlantic, the Indian and the Arctic. Now, there's a sea change ahead. Thanks to National Geographic, you'll soon see a fifth ocean on your maps.

They lived and worked with the crew last month as it mapped the Atlantic Ocean floor 1,500 feet below on an 186-foot research vessel off the coast of South Carolina.