Mt. Sibayak is a stratovolcano overlooking the town of Berastagi in North Sumatra, Indonesia. Although its last eruption in 1881, geothermal activity in the form of steam vents and hot springs remains high on and around the volcano. The vents produce crystalline sulfur, which was mined on a small scale in the past. Seepage of sulfurous gases has also caused acidic discolouration of the small crater lake.

One of the tallest Waterfall in Indonesia, it has 120 meter high and it located in Tongging Village, 45 Kilometers from Berastagi at the Northern end of Lake Toba.