Relatives of victims react as a rescue worker asks them to leave an area hit by landslides in Sumedang regency, West Java province, Indonesia on January 11, 2021. (Photo by Raisan Al Farisi/Antara Foto via Reuters)

A resident pushes their motorbike through flood waters caused by torrential rain in Semarang, central Java, Indonesia on February 23, 2021. (Photo by W.F. Sihardian/NurPhoto/Rex Features/Shutterstock)

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.

A Hindu worshipper throws vegetables into the crater as offerings during the Kasada Festival at Mount Bromo in Probolinggo, Indonesia's East Java province, August 1, 2015. Every year people gather for the annual festival where offerings of rice, fruit, vegetables, livestock or money are made to Hindu gods at the active volcano to ask for blessings and assure a bountiful harvest. (Photo by Reuters/Beawiharta)

A zookeeper handles a week-old newborn baby Langur at Bali Zoo on June 19, 2014 in Gianyar, Bali, Indonesia. Javan Langurs are found in Java, Bali and Lombok in Indonesia and are listed as a threatened species due to hunting, agricultural expansion and habitat loss. (Photo by Putu Sayoga/Getty Images)

This picture taken on May 23, 2017 shows visitors posing for photos along a path at an Indonesian hamlet dubbed “the rainbow village” in Semarang, central Java, that has become an internet sensation and attracting hordes of visitors. (Photo by Suryo Wibowo/AFP Photo)

Residents move the wreckage of cars that were swept away by flood in Bekasi, West Java, Indonesia, Friday, January 3, 2020. Severe flooding in greater Jakarta has killed scores of people and displaced tens of thousands others, the country's disaster management agency said. (Photo by Achmad Ibrahim/AP Photo)