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)

This picture taken on January 12, 2014 shows pet dogs, a yellow duck and a chicken in a skiing resort for a skiing competition in Sanmenxia, north China's Henan province. A tortoise beat a rabbit in a skiing competition held for pets and their owners in northern China, a report said on January 14. Cats and dogs faced off against a menagerie including a rooster and a yellow duck in a race to the finish line on snowy slopes in China's Hebei province, the state-run China News Service said. (Photo by AFP Photo)

Afghan paraglider Leeda Ozori, 21, walks after practicing in Kabul, Afghanistan September 14, 2015. She is one of a group of young Afghans taking to the skies of a capital where military helicopters and surveillance balloons are a far more familiar sight. Women in Afghanistan's conservative Muslim society are increasingly entering areas such as education, sports and the workplace, but most still wear the head-to-toe garment, the burqa. (Photo by Mohammad Ismail/Reuters)

The picturesque Zao Ski Resort, one of Japan's oldest and most popular ski destinations, is illuminated on February 10, 2007 in Yamagata Prefecture, Tohoku region of Honshu island, Japan. Coniferous trees such as the Aomori white fir lie covered with chrystallised ice and snow (described as “silver frost” or “snow monsters”) and attract visitors. (Photo by Koichi Kamoshida/Getty Images)

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)

A man sits on the window of a burning building before falling from it, in central Lahore May 9, 2013. Fire erupted on the seventh floor of the LDA plaza in Lahore and quickly spread to higher floors leaving many people trapped inside the building. At least three people fell from the high floors trying to avoid fire that engulfed the building, local media reports. (Photo by Damir Sagolj/Reuters)

A participant falls on vintage skis during a traditional historical ski race in the northern Bohemian town of Smrzovka February 21, 2015. (Photo by David W. Cerny/Reuters)