Lake Toba, North Sumatera, Indonesia

Lake Toba (Indonesian: Danau Toba) is a lake and supervolcano, 100 kilometres long and 30 kilometres wide, and 505 metres (1,666 ft) at its deepest point. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2°53′N 98°31′E / 2.88°N 98.52°E / 2.88; 98.52 to 2°21′N 99°06′E / 2.35°N 99.1°E / 2.35; 99.1.

It is the largest volcanic lake in the world. In addition, it is the site of a supervolcanic eruption that occurred about 74,000 years ago, a massive climate-changing event. The eruption is believed to have had a VEI intensity of 8. This eruption is believed to have been the largest anywhere on Earth in the last 25 million years.