A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)

Vietnamese military personnel in traditional dress take part in a parade celebrating the 40th anniversary of the end of the Vietnam War which is also remembered as the fall of Saigon, in Ho Chi Minh City, Vietnam, Thursday, April 30, 2015. (Photo by Dita Alangkara/AP Photo)

Ultra orthodox children stick their tongues out as snow falls on March 2, 2012 in Jerusalem, Israel. This is the first time in four years that the Israeli captial has experienced snow fall. (Photo by Uriel Sinai/Getty Images)

Vietnamese female traffic police officers march during a rehearsal for a military parade as part of the 40th anniversary of the fall of Saigon in southern Ho Chi Minh City (formerly Saigon City), Vietnam, on April 26, 2015. Vietnam marks the 40th anniversary of the fall of Saigon on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Department of Defense has said. (Photo by Reuters/Kham)

A weeping South Vietnamese mother and her three children are shown on the deck of this amphibious command ship being plucked out of Saigon by U.S. Marine helicopters in Vietnam, April 29, 1975. (Photo by AP Photo)

A partially frozen Niagara Falls is seen on the American side lit by lights during sub freezing temperatures in Niagara Falls, Ontario March 3, 2014. (Photo by Mark Blinch/Reuters)

Travellers ride their horse through the river during the Appleby Horse Fair on June 5, 2014 in Appleby, England. The Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685 and is one of the key gathering points for the Romany, gypsy and traveling community. The fair is attended by about 5,000 travellers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Nigel Roddis/Getty Images)

A Nepalese army solder stand next to a horse during the “Ghodejatra” Horse Race festival, which is organised by the Nepal Army, in Kathmandu, Nepal, April 7, 2016. Ghode Jatra, the horse racing festival of Nepal, celebrated on the New Moon day of mid March or early April is among the important celebrations of the Kathmandu Valley. Grand horse parade including various acrobatic style of shows are performed by Nepal military at Tundikhel-a fenced parade ground located in the heart of Kathmandu city. (Photo by Navesh Chitrakar/Reuters)