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.

Students learn how to use an airsoft gun from Taiwanese military instructors at Kaohsiung Municipal Sanmin Senior High School in Kaohsiung on January 11, 2024. Kaohsiung City launched a national defence education program using digital technology for all its high school students. The program also promotes drug prevention in cooperation with the Taiwan defense ministry. (Photo by Yasuyoshi Chiba/AFP Photo)

South Korean university students prepare for an establishment ceremony of the Reserve Officer Training Corps (ROTC) for female cadets at Sookmyung Women's University on December 10, 2010 in Seoul, South Korea. The South Korean defense ministry has agreed to admit women into it's college-based Reserve Officers' Training Program for the first time since the program began in 1963. (Photo by Chung Sung-Jun/Getty Images)

Lutricia Bock of Germany falls down as she performs during the ladies short program at the ISU European Figure Skating Championship in Bratislava, Slovakia, January 27, 2016. (Photo by David W. Cerny/Reuters)

Martin Lacey Jr. with a lion during the premiere of the Circus Krone program “Circus der Preistraeger” at Circus Krone on February 2, 2016 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

“The Buran program was a Soviet and later Russian reusable spacecraft project that began in 1974 at TsAGI and was formally suspended in 1993. It was a response to the United States Space Shuttle program”. – Wikipedia

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Madison Chock and Evan Bates of the U.S. compete during the ice dance short dance program at the ISU World Team Trophy in Figure Skating in Tokyo April 16, 2015. (Photo by Yuya Shino/Reuters)

Kim Yelim, of South Korea, competes in the women's free skate program during the figure skating competition at the 2022 Winter Olympics, Thursday, February 17, 2022, in Beijing. (Photo by Natacha Pisarenko/AP Photo)