The Walters Shoals is a group of submerged mountains

Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...

 off the coast of Madagascar

Madagascar

The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

. Despite being 700 kilometres from the coast, the tips of the some of the mountains are only 50 metres below the surface. The Walters Shoals are home to many species of fish, crustaceans, and mollusks.
It was discovered in 1963 by the South African Hydrographic Frigate SAS Natal captained by Cmdr Walters. When found it had a huge population of Galapagos sharks but they have since been fished out.
Name/
Height/
Summit Depth/
Latitude/
Longitude/
Region:

Walters Shoal/
4,750/
18/
-33/
44/
Indian (& adjacent Antarctic).