Indian Air Force soldiers toss their rifles as they perform during the full-dress rehearsal for Indian Air Force Day at the Hindon air force station on the outskirts of New Delhi October 6, 2015. (Photo by Anindito Mukherjee/Reuters)

In this November 18, 2015 photo, 9-year-old Mahiro Takano, center, three-time Japan karate champion in her age group practices in Nagaoka, Niigata Prefecture, north of Tokyo. Mahiro stars in singer Sia's latest music video "Alive", the just-released single from the singer's upcoming album. (Photo by Eugene Hoshiko/AP Photo)

Armed Syrian Turkmen villagers are seen near the northern Syrian village of Yamadi, near the Turkish-Syrian border, Syria, November 24, 2015. Turkey shot down a Russian warplane near the Syrian border on Tuesday saying it had repeatedly violated its air space, one of the most serious publicly acknowledged clashes between a NATO member country and Russia for half a century. (Photo by Reuters/Stringer)

People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

Couples (L-R) Chaiyut Phuangphoeksuk and Prontathourn Pronnapatthun, and Nichapatr Koomsombut and Pirat Rungthongoran run from sheep during their wedding ceremony at a resort in Ratchaburi province February 13, 2015. Three Thai couples took part in the wedding ceremony arranged by a resort themed around fun activities ahead of Valentine's Day. (Photo by Athit Perawongmetha/Reuters)

A young woman cools herself in a fountain in Budapest, Hungary July 6, 2015. Over the weekend, a heat wave has reached Hungary with temperatures topping 38 degrees Celsius (100.4 degrees Fahrenheit). (Photo by Laszlo Balogh/Reuters)

Onati Basque dancers go airborne as they perform Basque traditional dances while making their way to the front of Saint Mark's Catholic Church, Saturday, August 1, 2015, in Boise, Idaho. The annual Mass, conducted in English and Basque, was held at the church for the first time. (Photo by Kyle Green/Idaho Statesman via AP Photo)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)