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 passenger without pants waits for the subway train during “The No Pants Subway Ride” in Mexico City January 11, 2015. The event, the fifth organized in Mexico, is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Edgard Garrido/Reuters)

Fur hats are seen on display at the 2015 China Fur and Leather Products Fair in Beijing, January 15, 2015. Hundreds of domestic and foreign fur product companies take part in the fair which runs from January 13 to 16 at the National Convention Centre. (Photo by Jason Lee/Reuters)

Ukraine's Hanna Antonova competes during the 2015 World Pole Dance Championships held in Beijing, Sunday, April 12, 2015. (Photo by Ng Han Guan/AP Photo)

An iguana in Bali helped Julij Kopilović, age eight, from Slovenia, earn second runner-up in Amazing Animals. (Photo by Julij Kopilović/National Geographic)