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 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)

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 visitor and autumn foliage are reflected in the lake at Stourhead gardens in Wiltshire, Britain, November 2, 2018. (Photo by Toby Melville/Reuters)

A white ibis takes a shower at Lake Eola in Orlando, Florida, US on September 29, 2025. (Photo byRonen Tivony/NurPhoto/Rex Features/Shutterstock)

Located at the foot of the Rocky Mountains on the North Saskatchewan River, the rare phenomenon occurs each winter in the man-made lake. Photo: Ice bubbles in Abraham Lake. (Photo by Chip Phillips/Rex Features)

Yuccas catch fire as the Powerhouse fire makes a fast run toward Lake Hughes, south of Lake Hughes, California, on June 1, 2013. The 19,500-acre wildfire destroyed numerous homes overnight. (Photo by David McNew/Getty Images)

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)