Ethiopian Review

The seas off the Bahamas can seem like a swimming pool, but strip away the ocean (illustration at top), and the edges of the islands’ shallow Great Bahama Bank–where the light blue begins to turn dark in satellite images of the Caribbean–are revealed to be steep cliffs rising some 2 miles (3.2 kilometers) above a vast plain.

By comparison, Yosemite National Park’s nearly 5,000-foot-tall (1,520-meter) Half Dome (bottom) is a molehill.

For much of the seafloor, accurate computer images like the one at top are only now becoming possible.

Unmanned subs, mapping software, and other technology are finally improving to the point where we can map the oceans to the same level of detail as Mars, some 35 million miles away, according to a new National Geographic Channel documentary, Drain the Ocean, airing Sunday, August 9, at 9 p.m. ET/PT. (The National Geographic Channel is part owned by the National Geographic Society, which owns National Geographic News.)

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