Factory waste including dyes from the many textile factories in the region drain into a tributary of the Citarum river on August 27, 2018 outside Bandung, Java, Indonesia. (Photo by Ed Wray/Getty Images)

Two girls perform with their body painted for money fort purchasing food for breaking fasting in Bekasi, West Java, Indonesia on April 25, 2020, during the holy month of Ramadan. (Photo by Rezas/AFP Photo)

Farmers plant rice seedlings in a paddy in Karanganyar, near Solo, Central Java, Indonesia in this April 13, 2016 photo taken by Antara Foto. (Photo by Maulana Surya/Reuters/Antara Foto)

The Sunda lemur uses a special membrane to “fly” between trees while on the lookout for food in Java, Indonesia in the last decade of June 2024. (Photo by Dzulfikri/Solent News)

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)

A smiling gecko bursts through a gap in the bark to surprise photographer in West Java, Indonesia in the last decade of March 2025. (Photo by Dzul Duzulfikri/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.