People follow king penguins exploring their outdoor pen, during a so-called “penguin parade”, when the animals walk outside their enclosure and the visitors can walk behind them, at Zurich's Zoo in Zurich, Switzerland January 28, 2017. (Photo by Arnd Wiegmann/Reuters)

A dead red-tailed monkey hangs by its tail above the ground, in order to keep it away from ants, in the forest near the city of Mbandaka, Democratic Republic of the Congo, April 5, 2019. Bushmeat hunters are emptying Central Africa's forests at a high rate, researchers say. A growing appetite for wild meat in cities has ramped up the scale of hunting. Research shows around 6 million tonnes of bushmeat are sourced annually from the Congo Basin, whose forest spans across six countries and is second in size only to the Amazon. (Photo by Thomas Nicolon/Reuters)

The Wadi al-Salam cemetery, Arabic for “Peace Valley”, is seen in Najaf, south of Baghdad, Iraq August 3, 2016. The world's largest cemetery, in Iraq's Shi'ite holy city of Najaf, is expanding at double its usual rate as Shi'ite militias bury their dead from the war against Islamic State. The Wadi al-Salam cemetery, Arabic for “Peace Valley” has a special place in the hearts of Shi'ite Muslims as it surrounds the Mausoleum of their first imam, Ali Bin Abi Talib, a cousin and son-in-law of Prophet Mohammad. (Photo by Alaa Al-Marjani/Reuters)

People wearing costumes pose for a photograph as they participate in the annual “Zombie Walk” in Bordeaux, France on October 22, 2016. Several hundred people wearing costumes and makeup took part in the walk which was authorized despite the state of emergency. (Photo by Georges Gobet/AFP Photo)

A soldier walks on the bank of the river in central Pyongyang, North Korea on April 16, 2017. (Photo by Damir Sagolj/Reuters)

An Afghan woman walks with a child in the old city of Herat province, Afghanistan on October 15, 2018. (Photo by Mohammad Ismail/Reuters)

An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)