A donkey savors warming temperatures after a long winter at the zoo in Warsaw, Poland, on Wednesday, April 8, 2015. (Photo by Czarek Sokolowski/AP Photo)

Mercedes Formula One driver Lewis Hamilton of Britain sprays champagne at a grid girl as he celebrates his victory on the podium after the Chinese F1 Grand Prix at the Shanghai International Circuit, April 12, 2015. (Photo by Carlos Barria/Reuters)

Cheng Chen (R), a 27-year-old worker at a state-owned enterprise, poses for a photograph with his nephew who is wearing his home-made Iron Man armour, in Xuzhou, Jiangsu province April 13, 2015. It cost Cheng about 500 yuan ($81 USD) to make the armour, which weighs about 4 kilograms, with plastic boards and LED lights, local media reported. (Photo by Reuters/Stringer)

Models at the Sophia Webster presentation during London Fashion Week Spring Summer 2015 on September 14, 2014 in London, England. (Photo by Anthony Harvey/Getty Images)

A woman poses as she has her picture taken amid 1600 panda bear sculptures in Berlin August 5, 2013. Marking the 50th anniversary of its existence, on Monday the German branch of the World Wide Fund for Nature (WWF) environmental conservation organisation placed 1600 panda bear sculptures on front of Berlin's main train station to draw attention to the plight of the endangered species that serves as the NGO's mascot. There are currently 1600 panda bears alive in the wild, the organisation said in a press release. (Photo by Thomas Peter/Reuters)

A man speaks on his mobile phone on May 31, 2011 in New York City. In a new report by 31 scientists meeting at the World Health Organization's International Agency for Research on Cancer (WHO/IARC) it was found that using a mobile phone may increase your risk for certain kinds of brain cancers. While further scientific work will be conducted, the group of scientists from 14 countries classified cell phones in the carcinogenic category 2B, which is similar to the pesticide DDT and gasoline engine exhaust. (Photo by Spencer Platt/Getty Images)

Actress Emma Watson attends the World Premiere of Harry Potter and The Deathly Hallows – Part 2 at Trafalgar Square on July 7, 2011 in London, England. (Photo by Ian Gavan/Getty Images)

Members of the Gremlins Carnival Club, open the doors to their workshop to unveil for the first time their cart, Jungle Drums, which is their entry to this year's Bridgwater Carnival, on November 4, 2011 in Bridgwater, England. (Photo by Matt Cardy/Getty Images)