The Saya de Malha Bank is the largest submerged ocean bank in the world, part of the vast undersea Mascarene Plateau.
Saya de Malha lies northeast of Madagascar, southeast of the Seychelles, and north of the Nazareth Bank, the Cargados Carajos shoals, and the island of Mauritius, and currently falls mostly under International waters.
The closest land is tiny Agaléga (one of the Outer islands of Mauritius), some 300 km (190 mi) further west, followed by the southern Seychellois island of Coëtivy, some 400 km (250 mi) northwest. Mauritius administers the whole Saya de Malha Bank as a portion of it lies within its Exclusive Economic Zone.
Saya de Malha Bank consists of a series of narrow shoals, with depths from 17 to 29 m (56 to 95 ft) on the rim. They are arranged in a semicircular manner, around a space, the former lagoon, about 73 m (240 ft) deep, which slopes on the Southeast.
Some areas of the bank are shallow, less than 10 m (33 ft) below the surface. The shallowest sites known are Poydenot Rock, at a depth of 8 m (26 ft), and an unnamed site 145 km (90 mi) further northwest, with a depth of 7 m (23 ft).
According to en.wikipedia