LONDON - JUNE 04: A piece entitled “Entrance into wood” by Elke Krystufek goes on show at The Royal Academy Summer Exhibition on June 4, 2008 in London. In it's 240th year, the exhibition displays a wide range of recent work by both established and emerging artists. 10,000 artists submitted work for selection this year. (Photo by Peter Macdiarmid/Getty Images)

West German police arrest a young man, one of the angry crowd throwing stones at a bus full of Soviet guards making their way to the Soviet War Memorial, 20th August 1962. The crowd were incensed by the death of 18-year-old Peter Fechter, who was shot while trying to cross the Berlin Wall a few days earlier. (Photo by Central Press/Hulton Archive/Getty Images)

Models smoke during a break at Sevilla de Boda (Seville Wedding) fashion show in the Andalusian capital of Seville November 27, 2015. (Photo by Marcelo del Pozo/Reuters)

Female soldiers march during a military parade marking the country's Independence Day in Caracas, Venezuela, Wednesday, July 5, 2017. Venezuela is marking 206 years of their declaration of independence from Spain. (Photo by Ariana Cubillos/AP Photos)

A commuter gestures to Boris Johnson as he rides across Vauxhall Bridge in London, England on November 19, 2015. The London mayor was opening a cycle superhighway. (Photo by John Stillwell/PA Wire)

This picture taken on March 1, 2016 shows a man running a mobile pig mating service and waiting outside a customer's home with his male pig in a cage pulled behind his motorcycle in the northern province of Bac Ninh. (Photo by Hoang Dinh Nam/AFP Photo)

Nikolai Vasilyev, 62, dressed as Father Frost, Russian equivalent of Santa Claus, water-skis along the Yenisei River outside Siberian city of Krasnoyarsk, Russia, December 10, 2015. Vasilyev, a teacher of the Krasnoyarsk Aerospace Academy, constructed the self-made water skis to travel on the water surface. The skis are made of plastic foam and the sticks are designed to propel him forward. (Photo by Ilya Naymushin/Reuters)

A dancer poses with a new installation of art by British graffiti artist Banksy painted on the front door of the Hustler Club in New York, October 24, 2013. Known for his anti-authoritarian black-and-white stenciled images, which have sold at auction for upwards of $2 million, the British street artist is treating New Yorkers to a daily dose of spray-painted art – while eluding the police and incurring the wrath of New York Mayor Michael Bloomberg. (Photo by Eric Thayer/Reuters)