Last week scientists announced that the bank's reef system—already the largest and most biodiverse in the southern Atlantic Ocean—is nearly twice as vast as previously thought.

Using side-scan sonar to produce a 3-D map of the seabed, researchers found previously unknown reefs featuring pilqueta (above) and other corals between 60 and 220 feet (20 and 73 meters) deep off the southern coast of Bahia, Brazil.