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 combination photo shows Fata Kovacevic reacting near her flood-damaged house during floods May 20, 2014 (top) and the same place after floods October 8, 2014 in Topcic Polje. (Photo by Dado Ruvic/Reuters)

Participants, one of them loosing balance, jump in a sack race at a shopping center in Paris to win a 500 euros voucher (537 USD), on the first day of the winter sales in Paris, France, Wednesday, January 6 , 2016. The five-week 2016 winter sales start everywhere across France on Wednesday Jan. 6 and end on Feb. 16. (Photo by Francois Mori/AP Photo)

A woman walks through flood water during heavy downpour at a street in Genoa, Italy, 10 October 2014. At least one person died due to flooding after heavy rains caused the Bisagno river, which runs through Genoa city to overflow. Part of the city was in black-out with flooded streets and parked cars dragged away by the water's force. (Photo by Luca Zennaro/EPA)

Artist Kong Ning wears a wedding dress made from respirators to highlight concerns about air quality and pollution in Beijing, China on December 1, 2015. (Photo by Luo Xiaoguang/Xinhua Press/Corbis)

People look at a tanker after it fell into a caved-in area on a road in Xi'an, Shaanxi province, July 27, 2013. No casualty was reported in the accident, according to local media. (Photo by Reuters/Stringer)

A visitors to the National Galleries of Scotland view the work “A girl” of sculptor Ron Mueck on August 4, 2006 Edinburgh in Scotland. (Photo by Jeff J Mitchell/Getty Images)

A farmer harvests tobacco leaves at a plantation in the valley of Vinales, in the western Cuban province of Pinar del Rio, January 27, 2015. (Photo by Pilar Olivares/Reuters)