This family of warthogs regularly visited our campsite in the Ethiopian highlands so I set up a remote camera with a wide-angle lens to photograph them as they rummaged around for food. They just had a mud bath. (Photo by Will Burrard-Lucas/Caters News Agency)

Flames from a burning barricade lit by pro-democracy protesters is reflected in the windows of a passing bus as passengers watch on during a protest gathering in front of Mong Kok police station on September 22, 2019 in Hong Kong, China. Pro-democracy protesters have continued demonstrations across Hong Kong, calling for the city's Chief Executive Carrie Lam to immediately meet the rest of their demands, including an independent inquiry into police brutality, the retraction of the word “riot” to describe the rallies, and genuine universal suffrage, as the territory faces a leadership crisis. (Photo by Chris McGrath/Getty Images)

North Koreans perform during a mass game of “The Land of the People” at the May Day Stadium in Pyongyang, North Korea, Tuesday, June 25, 2019. (Photo by Jon Chol Jin/AP Photo)

A woman affected by tear gas is assisted during a May Day protest against austerity measures, in San Juan, Puerto Rico May 1, 2018. (Photo by Alvin Baez/Reuters)

Mae Zelinsky, left, and Betty O'Beda test ammunition on a .30 caliber rifle at a Remington Arms plant on April 30, 1943. Many women took over jobs that were left vacant when men went overseas to fight in World War II. (Photo by AP Photo)

Gunfire was brought to the steps of President Truman's Washington home, Blair House, as two assassins tried to kill the chief executive, November 1, 1950. One of the gunmen, Oscar Collazzo of New York, lay wounded at the bottom of Blair House's front steps after the president's police guard had finished their work, at the cost of one guards' life, Dec. 9, 1950. The second gunman was killed. (Photo by Harvey Georges/AP Photo)

Cambridge students the morning after the Trinity and Jesus college May Balls in Cambridge, United Kingdom on June 19, 2018. Students at Cambridge University celebrate the end of the academic year with the May Balls. (Photo by South West News Service)

Long row of shiny new Flying Fortresses, part of huge reserves being built up in Britain for D-Day, stands by to be flown to combat units as replacements, May 25, 1944. (Photo by AP Photo)