Houthi followers perform the traditional Baraa dance ahead of a demonstration against the Saudi-led air strikes in Yemen's capital Sanaa August 24, 2015. The nothern-based Houthis, a Shi'ite Muslim group, took control of Sanaa last September. Arab countries intervened in the conflict in March to halt a Houthi advance into the south which caused the Saudi-backed government to flee to Riyadh from its refuge in the southern port of Aden. (Photo by Khaled Abdullah/Reuters)

A Russian-made rifle, carried by this woman when she was captured in Nearby Brush, is slung around her neck by South Vietnamese soldiers before they began their interrogation of her as Viet Cong suspect near AP La Ghi in Vietnam, August 25, 1965. The girl behind the woman, also was captured in the brush. (Photo by AP Photo)

Emma Coburn (L) and Colleen Quigley of the U.S. look at the scoreboard after competing in the women's 3,000 metres steeplechase final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 26, 2015. (Photo by David Gray/Reuters)

A Thai veterinarian takes a picture of a 2-year-old orangutan during a health examination at Kao Pratubchang Conservation Centre in Ratchaburi, Thailand, August 27, 2015. Thai veterinarians from the Department of National Park Wildlife, and Plant Conservation conducted a health check of 14 orangutans for preparation for the repatriation to their country of origin, Indonesia. (Photo by Athit Perawongmetha/Reuters)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

A man photographs the main engines of the space shuttle orbiter Discovery on display at the Udvar-Hazy Smithsonian National Air and Space Annex Museum in Chantilly, Virginia August 28, 2015. Shuttle Discovery had 27 years of service and flew 39 times before being retired in 2011. (Photo by Gary Cameron/Reuters)

Recording artists Demi Lovato (L) and Iggy Azalea perform on the Pepsi Stage, during the 2015 MTV Video Music Awards, at The Orpheum Theatre on August 30, 2015 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images for MTV)

A Nepalese boy gets ready to perform a stick dance during a rally held to pay tribute to the victims of an earthquake, in Bhaktapur, Nepal, Wednesday, September 2, 2015. Two powerful earthquakes in April and May devastated the Himalayan nation killing more than 8,800 people. (Photo by Niranjan Shrestha/AP Photo)