A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)

A woman plays around as she walks across a glass-bottomed suspension bridge in a scenic zone in Pingjiang county in southern China's Hunan province Thursday, September 24, 2015. The bridge, 300 meters (984 feet) long and 180 meters (590 feet), opened to visitors on Thursday for the first time since its conversion from a regular suspension bridge was completed. (Photo by Chinatopix Via AP Photo)

A priest sprinkles holy water on a believer during the Orthodox Easter service in the Holy Transfiguration Cathedral in the rebel-controlled city of Donetsk, Ukraine on May 2, 2021. (Photo by Alexander Ermochenko/Reuters)

A staff member removes a coffin from a room of the “Corpse Hotel” in Kawasaki, Japan, April 20, 2016. Many so-called corpse hotels have emerged as a flourishing business in the city following a crunch in crematoriums. Families can rent a room in Sousou on a daily charge of 9,000 Japanese yen (£58, €74, $84) to keep the body of the deceased relative for up to four days until they find a crematorium. (Photo by Thomas Peter/Reuters)

A displaced Iraqi girl, who fled her home, cries during a battle between Iraqi forces and Islamic State militants, near Badush, Iraq, March 16, 2017. (Photo by Reuters/Stringer)

Photo taken on November 5, 2015 shows flood in Bento Rodrigues, a town in the southeastern Brazilian state of Minas Gerais, after a dam at a mining waste site burst early Thursday. An iron ore tailings dam in the southeast Brazilian state of Minas Gerais collapsed Thursday, killing at least 15 people, according to local media reports. (Photo by Agencia Estado/Xinhua Press/Corbis)

“The Net thrower”. The fisherman are conducting activities on Situgunung Lake. Photo location: Situgunung lake, Sukabumi, West Java, Indonesia. (Photo and caption by Dody Kusuma/National Geographic Photo Contest)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)