Sumatra Lake Toba
Indonesia's Lake Toba in Sumatra is 100km (62 miles) long and 29km (18 miles) wide. It is the largest volcanic lake in the world. The natural beauty of Lake Toba is astounding; Samosir Island rests in the center of the lake and provides the perfect escape from urban sprawl of Medan - Indonesia's fourth-largest city.
The formation of Lake Toba, known locally as Danau Toba, is thought to be one of the most colossal events in Earth's history.