Sailors from the Indonesian Navy carry a victim of a boat sinking last week off the coast of Indonesia, on December 21, 2011 in Banyuwangi, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

A flying lemur glides through the air in West Java, Indonesia in the first decade of October 2023. The photographer said the animal veered away from him at the last minute. (Photo by Dzul Dzulfikri/Animal News Agency)

Indonesian soldiers wearing facemasks and personal protective equipment take a part in a sack race during games to celebrate ahead of the country's 75th Independence Day in Surabaya, East Java on August 14, 2020. Indonesia will mark its 75th Independence Day on August 17. (Photo by Juni Kriswanto/AFP Photo)

Located in East Java, Indonesia, Kawah Ijen is a volcano is home to the largest acidic crater lake in the world. What turns the waters of the lake in the 1 km caldera its beautiful turquoise color are the highly sulfuric gases emitted from the volcano underneath.

Indonesian activists covered with sludge from the mud volcano hold a protest during five year anniversary of the Sidoarjo mud eruption on May 29, 2011 in the subdistrict of Porong in Sidoarjo, East Java, Indonesia. (Photo by Ulet Ifansasti/Getty Images)

A Hindu villager rides a motorcycle past an altar ahead of the annual Kasada festival at the Mount Bromo in Indonesia's East Java province, July 30, 2015. The Kasada festival will be held on August 1, when the worshippers throw offerings such as livestock and other crops into the volcanic crater of Mount Bromo to give thanks to the Hindu gods for ensuring their safety and prosperity. (Photo by Reuters/Beawiharta)

A female participant of the Bela Negara – “defend the nation” – programme applies camouflage face paint on another participant's face at a training centre in Rumpin, Bogor, West Java, Indonesia June 2, 2016. (Photo by Darren Whiteside/Reuters)