Segara Anak is a crater lake in the caldera that formed during the explosive volcanic eruption of Mount Samalas in 1257.

The volcanic cone Gunung Barujari is at the eastern end of the lake and is responsible for its crescent shape.

[1] The surface of Segara Anak is 2,004 metres (6,575 ft) above mean sea level (AMSL) and is Indonesia's second-highest caldera lake with an active volcano.

Segara Anak is today a popular spot for fishing, and some locals make a living from this.

The eruption may have been the cause of decreased global temperatures for a few years and may have even been a triggering factor for the Little Ice Age.