Workers adjust rails at the bed of a drained area of a lake used for the production of salt at the Sasyk-Sivash lake near the city of Yevpatoria, Crimea, September 25, 2015. The area has a long tradition of salt production, prepared from salt flats flooded with water from the Black Sea. (Photo by Pavel Rebrov/Reuters)

Costumed participants of a lacquer and leather ship, the so-called “Torture Ship”, kiss before putting out to Lake Constance for a pleasure cruise at the harbor of Friedrichshafen, Germany, 29 June 2019. Hundreds of leather and rubber fans set sail for the boat trip through the night on Lake Constance. (Photo by Daniel Kopatsch/EPA/EFE)

A couple covered in mud wait for it to dry at the Salt-works lakes near the Black Sea town of Burgas in Bulgaria on July 25, 2019. Thousands of tourists visit the red salt lakes for mud baths, which are believed to help the healing of muscular disorders and rheumatism. (Photo by Nikolay Doychinov/AFP Photo)

Fishermen are seen near thousands of fish found dead at Lake Maninjau due to lack of oxygen levels at the bottom of the lake and bad weather that hit the area in Agam, West Sumatra Province, Indonesia on April 29, 2021. (Photo by Muhammad Arif Pribadi/Antara Foto via Reuters)

A white yak sits on the lakeside of Namtso on May 19, 2024 in Lhasa, Xizang Autonomous Region of China. As temperature rises and ice melts, Lake Namtso is entering its tourism season. An event celebrating the melting of frozen water of Lake Namtso is held on May 19. (Photo by Jin Wei/VCG via Getty Images)

A man rows a boat on the Dal Lake as a woman holds an umbrella during snowfall in Srinagar February 19, 2015. (Photo by Danish Ismail/Reuters)

A flock of starlings flies over Lake Leman on an autumn morning in the Lavaux near Grandvaux, Switzerland October 20, 2016. (Photo by Denis Balibouse/Reuters)

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.