U.S. Air Force wounded warrior, Capt. Sarah Evans, jumps rope in a gym in San Antonio, Texas. Evans was diagnosed with cancer while deployed to Afghanistan and was medically evacuated back to the United States where her leg was amputated. (Photo by Master Sgt. Jeffrey Allen/U.S. Air Force)

North Korean children wave to people on a Chinese tourist boat on the banks of Yalu River near the Chongsong county of North Korea, opposite the Chinese border city of Dandong, May 8, 2011. (Photo by Jacky Chen/Reuters)

A serviceman walks near an APC while a helicopter flies on the position of the Ukrainian troops in Donetsk region on August 9, 2014. Fighting with pro-Russian separatists in eastern Ukraine has left 13 troops dead in the last 24 hours, Ukraine's military said Saturday. (Photo by Anatolii Stepanov/AFP Photo)

A boy pushes a donkey cart loaded with bundles of cotton blooms that were collected by women cotton pickers in Meeran Pur village, north of Karachi September 25, 2014. Women make up the bulk of Pakistan's half a million cotton producers, but labour rights activists say they are often exploited by overseers, who often withhold their wages and may subject some of them to sexual harassment. (Photo by Akhtar Soomro/Reuters)

Community members look for the nameplates of their loved ones Tuesday, December 9, 2014 at Myers Funeral Service and Crematory in Porterville, Calif. during the 20th year of the memorial tree lighting. (Photo by Chieko Hara/AP Photo/The Porterville Recorder)

Honorable Mention: “The Storm”. During I was taking photo with my nephew, the storm came and I caught this beautiful moment. Photo location: Kocaeli, Turkey. (Photo and caption by Aytül Akbaş/National Geographic Photo Contest)

In this Thursday, January 29, 2015 photo, the backseat of a rented 1957 Buick is packed to the brim with flowers, to be transported to Havana from San Antonio de los Banos, Cuba. Every Monday and Thursday morning, self-employed flower vendor Yaima Gonzalez Matos leaves her home to visit a dozen farmers who sell her sunflowers, roses, lilies and other blooms. She loads the flowers into the rented American classic and delivers to customers in the capital. (Photo by Ramon Espinosa/AP Photo)

Singer Ariana Grande performs during the 2014 MTV Europe Music Awards at the SSE Hydro Arena in Glasgow, on November 9, 2014. (Photo by Toby Melville/Reuters)