The Ross Ice Shelf is the largest ice shelf of Antarctica (an area of roughly 487,000 square kilometres (188,000 sq mi) and about 800 kilometres (500 mi) across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 kilometres (370 mi) long, and between 15 and 50 metres (50 and 160 ft) high above the water surface. Ninety percent of the floating ice, however, is below the water surface.