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)

Russian pop art photographer Sergey Chilikov captures a nation liberated from the social oppression of late-era Soviet rule – at parties, in the streets, and bouncing high. His exhibition, Photoprovocations, will be at Photo London, 19-22 May. Here: Yoshkar-Ola, Matrosova Street (1995). (Photo by Sergey Chilikov)

“Falling Back To Earth” promises to be both spectacular and meditative, and presents a beautiful, thought-provoking vision of our relationship with the earth and with each other. (Photo by Dave Hunt/EPA)

Visitors look over masses of ice formed around the Canadian “Horseshoe” Falls in Niagara Falls, Ontario, Canada, Thursday, February 19, 2015. (Photo by Aaron Lynett/AP Photo/The Canadian Press)

A model falls over on the runway during the SECCRY Hu Sheguang Collection 2014 Show during Mercedes-Benz China Fashion Week, March 30, 2014, in Beijing. (Photo by Lintao Zhang/Getty Images)