Lake Toba, Indonesia

Lake Toba is a large natural lake occupying the caldera of a supervolcano. The lake is about 100 kilometres long, 30 kilometres wide, and up to(1,666 ft) deep. Located in the middle of the northern part of the Indonesian island of Sumatra, with a surface elevation of about (2,953 ft).
It is the largest lake in Indonesia and also the largest volcanic lake in the world.

Lake Toba is the site of a massive supervolcanic eruption estimated at VEI 8 that occurred 69,000 to 77,000 years ago, representing a climate-changing event. It is the largest known explosive eruption on Earth in the last 25 million years.

It had global consequences for human populations: it killed most humans living at that time and is believed to have created a population bottleneck in central east Africa and India, which affects the genetic make up of the human world-wide population to the present.

It has been accepted that the eruption of Toba led to a volcanic winter with a worldwide decrease in temperature between 3 to 5 degree celcius.

Since the major eruption 70,000 years ago, eruptions of smaller magnitude have also occurred at Toba.
The small cone of Pusukbukit formed on the southwestern margin of the caldera and lava domes. The most recent eruption may have been at Tandukbenua on the northwestern caldera edge, suggested by a lack of vegetation that could be due to an eruption within the last few hundred years.

The flora of the lake includes various types of phytoplankton, emerged macrophytes, floating macrophytes, and submerged macrophytes, while the surrounding countryside is rainforest including areas of Sumatran tropical pine forests on the higher mountainsides.