A bride gets ready during a mass wedding ceremony in the old quarters of Delhi February 20, 2015. A total of 12 couples took their wedding vows on Friday during the mass wedding ceremony organised by a Hindu religious organisation, an organiser said. (Photo by Ahmad Masood/Reuters)

A Tibetan rider fires his weapon as he perfoms his riding skills at the Qinghai Yushu Horse Racing Festival on July 27, 2007 in Yushu County of Yushu Tibetan Autonomous Prefecture, Qinghai Province, northwest China. The Horse Racing Festival of Tibetan nomads in Yushu Prefecture falls in late July and early August on the Tibetan calendar. During the festival, various equestrian skills will be performed along with singing, dancing and costume shows. (Photo by China Photos/Getty Images)

A pro-Russian rebel guards a captured former Ukrainian Army checkpoint outside Vuhlehirsk, Donetsk region, eastern Ukraine, Thursday, February 5, 2015. The rebels have closed in around the town in a strategy they triumphantly refer to as the Debaltseve cauldron. Separatists recently burst through government lines in the rural settlement of Vuhlehirsk. (Photo by Vadim Braydov/AP Photo)

Two styles of cleaned bird's nest, Yan Zhan (L) and Su Zhan (R) await repacking at a processing plant in Kuala Lumpur, February 17, 2015. Prized in China for is alleged health benefits for hundreds of years, nests made from swiftlets' saliva are being mixed into coffee and cereal as the Southeast Asian producers of the delicacy seek to broaden its appeal, and their profit margins. The nests are among the world's most expensive foods, selling for up to $2,500 a kg and the swiftlets that weave them are indigenous to Indonesia, Malaysia, Thailand and Vietnam. (Photo by Olivia Harris/Reuters)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

“Thunderstruck”. Summer stom. A super cell formed off the coast of New Zealand, intensified and swept across Christchurch and North Canterbury, February 23, 2014. Photo location: Christchurch, New Zealand. (Photo and caption by David Hardy/National Geographic Photo Contest)

“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

“A Mothers Tail”. A baby cub pulls on his mother's tail to get attention. Photo location: Masai Mara, Kenya. (Photo and caption by Tori Marsh/National Geographic Photo Contest)