Mountains in the sea rivaling the Rocky Mountains, canyons as grand as the Grand Canyon, deep trenches paralleling continental margins and island arcs that are the deepest places in the oceans -- all these and more have been revealed by science and survey ships plying the world ocean.
In the waters of the United States, the vast majority of canyons, basins, banks, and seamounts were discovered by Coast and Geodetic Survey ships engaged in bathymetric mapping projects. The great salt domes and the bizarre basin topography of the Texas-Louisiana slope were first discovered by C&GS ships conducting systematic mapping operations.