A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

Choristers from a Norwegian choir on a visit to New York take photographs in Times Square. (Photo by Vecchio/Three Lions/Getty Images). Circa 1956

The players of Denmark huddle prior to the FIFA Women's World Cup qualifier match between Denmark and Sweden at Viborg Stadion on September 4, 2018 in Viborg, Denmark. (Photo by Lars Ronbog/FrontZoneSport via Getty Images)

New York nightclub owner Jack L Hickman spends his free time marching around Times Square with a sign that reads “The only good communist is a dead communist”. (Photo by Peter Keegan/Keystone/Getty Images). 26th April 1965

An Iraqi man comforts his 4-year-old son at a regroupment center for POWs of the 101st Airborne Division near An Najaf, Iraq, March 31, 2003. The man was seized in An Najaf with his son and the U.S. military did not want to separate them. (Photo by Jean-Marc Bouju/Associated Press)

Lightning strikes the Willis Tower (formerly Sears Tower) in downtown on June 12, 2013 in Chicago, Illinois. (Photo by Scott Olson/Getty Images)

Castro's soldiers at Playa de Giron, Cuba, after thwarting the ill-fated US backed 'Bay of Pigs' invasion. (Photo by Graf/Getty Images). April, 1961

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)