Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)

North Korean leader Kim Jong Un, his wife Ri Sol Ju and Song Tao, head of the International Department of Communist Party of China (CPC) Central Committee, applaud with ballet dancers in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang April 17, 2018. (Photo by Reuters/KCNA)

An Indian labourer carries a sack of plastic bottles on his head near one of the largest disposal sites in north-east India, ahead of the “World Environment Day” in Boragaon area of Guwahati on June 4, 2018. World Environment Day is marked annually on June 5, and aims at promoting awareness and action to protect the environment. (Photo by Biju Boro/AFP Photo)

Cristine Angelie Garcia (C), 24, rides a jeepney on her way to work at a call centre for the midnight shift in Taguig city, Metro Manila, Philippines October 3, 2016. “Maybe there is another way where people do not need to die”, she said, adding she felt safer walking the streets at night. “I'm on Duterte's side. Maybe he's just misunderstood because he grew up on the streets”. (Photo by Ezra Acayan/Reuters)

Residents walk past electoral posters in Port-au-Prince, Haiti, January 28, 2017. (Photo by Andres Martinez Casares/Reuters)

A man smokes a marijuana cigarette to celebrate 420, in Times Square amid the coronavirus disease (COVID-19) pandemic in New York City, New York, U.S., April 20, 2021. (Photo by Carlo Allegri/Reuters)

Birds are seen at Kizilirmak Bird Paradise in Turkey's Samsun on April 22, 2021. Kizilirmak Delta Bird Sanctuary, which is on the UNESCO World Heritage Tentative List and hosts 359 to 487 species of birds in Turkey, became more active with the arrival of spring. (Photo by Mehmet Kumcagiz/Anadolu Agency via Getty Images)

United States Air Force Academy graduates cheer as the United States Air Force Thunderbirds fly over the graduation for the Class of 2021 at Falcon Stadium on May 26, 2021 in Colorado Springs, Colorado. Chairman of the Joint Chiefs of Staff General Mark A. Milley gave the commencement address to the 1,019 graduates from the academy. (Photo by Michael Ciaglo/Getty Images)