People pose for a photo with certificates after swimming in the ocean for the 121st annual Coney Island Polar Bear Club's New Year's Day plunge at Coney Island beach in the Brooklyn borough of New York, New York, USA, 01 January 2024. (Photo by Sarah Yenesel/EPA)

Mount Lewotobi Laki-laki volcano spews vulcanic materials during an eruption as seen from Pululera village in East Flores Regency, East Nusa Tenggara province, Indonesia, on April 27, 2025. (Photo by The Centre for Volcanology and Geological Hazard Mitigation (PVMBG)/Handout via Reuters)

A member of the Air Force's Wings of Blue Parachute Demonstration Team salutes as he jumps out of an aircraft, during the opening ceremony of Aviation Nation 2017 Nellis Air and Space Expo at Nellis Air Force Base, Nev., November 10, 2017. (Photo by Senior Airman Kevin Tanenbaum/Reuters/U.S. Air Force)

An Egyptian man shows off his motorcycle skills, following the outbreak of the coronavirus disease (COVID-19), in Cairo, Egypt on July 17, 2020. (Photo by Mohamed Abd El Ghany/Reuters)

View of the Villarrica volcano taken from Pucon, some 800 kilometres south of Santiago, showing signs of activity on December 06, 2017. (Photo by Christian Miranda/AFP Photo)

Visitors look up at mock-ups of dinosaur skeletons inside the Museum of Natural History in Pyongyang on September 28, 2016. (Photo by Ed Jones/AFP Photo)

Italy's Federica Brignone's helmet is seen after their run at the FIS Alpine Ski World Cup in Garmisch-Partenkirchen, Germany, on January 25, 2025. (Photo by Gintare Karpaviciute/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.