Pupils look at an orphaned baby elephant at the David Sheldrick Elephant Orphanage within the Nairobi National Park, near Kenya's capital Nairobi October 15, 2014. The orphanage under the David Sheldrick Wildlife Trust is operated by Daphne Sheldrick, wife of late famous naturalist David William Sheldrick. The orphaned elephants raised by the trust will be returned to join the undomesticated elephant population in Tsavo National Park, where David was the founder warden from 1948 to 1976, when they mature, usually between eight to 10 years old. (Photo by Goran Tomasevic/Reuters)

An adult chimp plays with a young chimp at Chimp Haven in Keithville, La., Monday, February 18, 2013. One hundred and eleven chimpanzees will be coming from a south Louisiana laboratory to Chimp Haven, the national sanctuary for chimpanzees retired from federal research. (AP Photo/Gerald Herbert)

An Iranian soldier guards two German tourists near the Iranian-Turkish border during World War II. Since the British occupation of Iran, all Axis nationals are being expelled from the country. (Photo by Three Lions/Getty Images). Circa 1941

Flames from the Falls Fire burn on a hillside along South Main Divide Road in the Cleveland National Forest as firefighters drive through the area on Monday, August 5, 2013. (Photo by Kurt Miller/AP Photo/The Press-Enterprise)

A 6-month old female giant panda cub, an offspring of Xing Xing, formerly known as Fu Wa and Liang Liang, formerly known as Feng Yi, plays at the Giant Panda Conservation Center at the National Zoo in Kuala Lumpur, Malaysia, Thursday, February 18, 2016. (Photo by Joshua Paul/AP Photo)

A woman aims a World War II machine gun at a military show during celebration of the Defenders of the Fatherland Day in St.Petersburg, Russia, Tuesday, February 23, 2016. The day, celebrated in Russia on February 23, honors the nation's military and is a nationwide holiday. (Photo by Dmitri Lovetsky/AP Photo)

A military band prepares to play the national anthems before Cuban President Raul Castro welcomes U.S. President Barack Obama at the Palacio de la Revolucion in Havana March 21, 2016. Barack Obama on Sunday became the first US president in 88 years to visit Cuba, touching down in Havana for a landmark trip aimed at ending decades of Cold War animosity. (Photo by Jonathan Ernst/Reuters)

A sauna building sits above the clouds at 9,280 feet (2,752 meters) at the Rifugio Lagazuoi in the Dolomite Mountains near Cortina d' Ampezzo in northern Italy July 17, 2015. The Dolomites are home to the Dolomiti Bellunesi National Park and were declared a UNESCO World Heritage Site in August, 2009. (Photo by Bob Strong/Reuters)