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.

In the coming months, the Ocean Seeker will undergo a $2-million retrofit to carry sophisticated sonars and lasers capable of capturing highly detailed images of the floor of the Atlantic Ocean.

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.