Brazilian natives of the Pareci tribe play head football with a hand-made ball for a demonstration, during the first day of the International Games of Indigenous Peoples, in Cuiaba, state of Mato Grosso, on November 10, 2013. 1500 natives from 49 Brazilian ethnic groups and from another 17 countries are gathering in Cuiaba until November 16 to compete in some 30 athletic disciplines, many of their own. (Photo by Christophe Simon/AFP Photo)

Volunteers from the South Carolina Aquarium release a rehabilitated Loggerhead Sea Turtles on May 18, 2012 in Isle of Palms, South Carolina. The turtle was one of two that were rescued and nursed back to health by the sea turtle hospital at the aquarium. (Photo by Richard Ellis)

Thinku dancers perform during the "Senor del Gran Poder" (Lord of Great Power) parade in La Paz, May 30, 2015. According to local media, thousands of dancers participated in this annual pagan religious celebration. REUTERS/David Mercado

A David Cameron look-alike poses with a polar bear model outside the Houses of Parliament as part of a Greenpeace protest on May 13, 2011 in London, England. The environmental charity Greenpeace arranged the protest to highlight the first anniversary of David Cameron’s speech when he pledged to make his new government the greenest ever. In April 2006 Mr Cameron traveled by huskie-drawn sledge when he visited the island of Svalbard in Norway to witness the effects of climate change. (Photo by Oli Scarff/Getty Images)

In this photo illustration a package of Nicotine Gum, which is advertised as helping people stop smoking cigarettes, is seen on January 10, 2012 in Miami, Florida. A study published in the journal Tobacco Control on Monday, reported that the nicotine alternatives, like Nicotine Gum, have no lasting effect on people trying to quit their smoking habit. (Photo illustration by Joe Raedle/Getty Images)

The artwork of Giant Horse Aboriginal rock art galleries in the Quinkan Country is seen on June 19, 2011 in Laura, Australia. The ancient aboriginal rock art in this region is some of the largest and oldest in the world, dating back over 15,000 years. Paintings, stencil art and engravings cover thelands traditionally home to the Kuku, Yalanji, Guugu Yimithirr and Kuku Thaypan people. As a UNESCO-identified top 10 rock art site in the world, international travelers visit the area to learn and understand the aboriginal culture through the artwork. (Photo by Mark Kolbe/Getty Images)

Members of the American Civil War Society take part in a mock battle in the grounds of Cusworth Hall, South Yorkshire on July 2, 2011 in Doncaster, United Kingdom. Enthusiasts from all walks of life are taking part in re-enacting scenes from the American Civil War and in 'living history' events which are as authentic as possible. (Photo by Christopher Furlong/Getty Images)