Mount Rinjani (Sasak: Gunong Rinjani, Indonesian: Gunung Rinjani) is an active volcano in Indonesia on the island of Lombok. Administratively the mountain is in the Regency of North Lombok, West Nusa Tenggara (Indonesian: Nusa Tenggara Barat, NTB). It rises to 3,726 metres (12,224 ft), making it the second highest volcano in Indonesia. It is also the highest point in the Indonesian province of West Nusa Tenggara. Adjacent to the volcano is a 6-by-8.5-kilometre (3.7 by 5.3 mi) caldera, which is filled partially by the crater lake known as Segara Anak or Anak Laut (Child of the Sea), due to the color of its water, as blue as the sea (laut). This lake is approximately 2,000 metres (6,600 ft) above sea level and estimated to be about 200 metres (660 ft) deep; the caldera also contains hot springs. The lake and mountain are sacred to the local ethnically Sasak people and also to some Hindus, and are the site of religious rituals. UNESCO made Mount Rinjani Caldera a part of the Global Geoparks Network in April 2018. Its catastrophic eruption in 1257 was the largest volcanic eruption in the last 2000 years.