Largest underground lake

The world largest underground lake is Lake Vostock in Antarctica. It is the largest of Antarctica's sub-glacial lakes, and is a freshwater lake located approximately 4,000 m (13,100 ft) beneath the surface of the ice. At this depth underground, the lake is approximately 500 m (1,600 ft) below mean sea level. Measuring 250 km (160 miles) long by 50 km (30 miles) at its widest point, the lake covers an astonishing area of 12,500 square km (4,830 square miles) and an average depth of 432 m (1,417 ft), giving it an estimated volume of 5,400 cubic km (1,300 cubic miles).