Chechen Interior Minister Ruslan Alkhanov greets participants of the military parade to mark the Victory Day in Grozny, Russia, May 9, 2015. Russia marks the 70th anniversary of the end of World War Two in Europe on Saturday with a military parade, showcasing new military hardware at a time when relations with the West have hit lows not seen since the Cold War. (Photo by Reuters/Host Photo Agency/RIA Novosti)

Student protestors, including one girl with a camera, struggle with soldiers from the Chinese Army, the PLA. Tiananmen Square, 1989. (Photo by Jeff Widener/Associated Press)

A chimpanzee bottle-feeds a lamb at Southam Zoo Farm in Warwickshire. The owners of the zoo, Mr and Mrs Clews, bring up many of the animals as their pets; the animals, are, as a result, of a friendly disposition. (Photo by Fox Photos/Getty Images). 23rd August 1968

A female street art collective has set a new Guinness World Record to create the largest spray-painted mural by multiple artists. Over 100 international female street artists came together to create the continuous mural in south London’s Leake Street Tunnel, made famous by Banksy, on March 8, 2014. The record was broken as part of all-female street art event Femme Fierce, the largest of its kind in the UK, which aims to celebrate women street artists across the world. Photo: Zabou's witty graffiti. (Photo by Dez Mighty/Susan Mackey)

Members of the U.S. Army 173rd Airborne Brigade stand at attention as a Ukrainian folk dance group performs at the opening ceremony of the “Rapid Trident” NATO military exercises on September 15, 2014 near Yavorov, Ukraine. The two-week exercises include participating units from a variety of NATO and NATO-associate countries as well as Ukrainian troops. Meanwhile fighting between pro-Russian separatists and Ukrainian armed foces has flared again in eastern Ukraine in a battle for the control of Donetsk airport despite the tenuous ceasefire. (Photo by Sean Gallup/Getty Images)

An American flag flutters on a young tree stripped of bark after a massive tornado passed through the town killing at least 116 people May 24, 2011 in Joplin, Missouri. The tornado that ripped through the town of about 50,000 people May 22, is being called the deadliest single tornado in the U.S. in 60 years. (Photo by Julie Denesha/Getty Images)

Ammunition airlift into besieged Khe Sanh, Operation Pegasus, April 1968. (Photo by Larry Burrows/AP Photo)

A 40-foot sculpture of the swimmer Rebecca Adlington was unveiled at the Serpentine in London’s Hyde Park on July 25, 2016 to launch a campaign by Kelloggs to encourage the public to support Team GB at the Rio Olympics. (Photo by David Parry/PA Wire/Barcroft Images)