People protect themselves behind a trash can as anti-riot olice fires water cannon to disperse thousands of people demonstrating following the death of Berkin Elvan, a teenage boy wounded in mass anti-government demonstrations last year, on March 11, 2014 near the Middle East Technical University (ODTU) in Ankara. Elvan's story – he spent 269 days in a coma – gripped the nation and became a symbol of the heavy-handed tactics used by police to reign in the biggest demonstrations against Prime Minister Recep Tayyip Erdogan since he came to power in 2003. (Photo by Adem Altan/AFP Photo)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

A woman shouts asking for help during an eviction in Rio de Janeiro, Brazil, Friday, April 11, 2014. Squatters in Rio de Janeiro are clashing with police after a Brazilian court ordered that 5,000 people be evicted from abandoned buildings of a telecommunications company. Officers have used tear gas and stun grenades to try to disperse the families. (Photo by Silvia Izquierdo/AP Photo)

Hucul horses play in the wild meadows and forests near Odrzychowa in southeastern Poland on October 18, 2014. Huculs, a primitive breed of horse, escaped total extinction due to the efforts of scientists and Polish farmers. (Photo by Janek Skarzynski/AFP Photo)

Young Slovaks dressed in traditional costumes throw a bucket of water at a girl as part of Easter celebrations in the village of Trencianska Tepla, Slovakia, April 9, 2012. Slovakia's men splash women with water to symbolize youth, strength and beauty for the upcoming spring season. (Photo by Samuel Kubani/AFP)

Four-year-old Solaris Arias (right) jumps through water spraying from an open fire hydrant in Providence, Rhode Island, on June 20, 2012. Much of the state remained under a heat advisory Tuesday afternoon because of the steamy air mass that has moved into the region resulting in temperatures in the 90s. (Photo by Steven Senne/AP Photo)

Burdened with a shawl full of her belongings, a woman stops for a rest on the road between Julaca and Puno in Peru. (Photo by Three Lions/Getty Images). Circa 1955