A panda bear sits on a logs in a zoo on January 15, 2015 in Hangzhou, China. (Photo by Feature China/Barcroft Media)

Two stags fight in a wildlife park in Aurach near Kitzbuehel, in the Austrian province of Tyrol. (Photo by Kerstin Joensson/Associated Press)

Pernille Ferdinandsen receives a neck tattoo from Peter Madsen during the third Copenhagen Ink Festival which opened Thursday May 9, 2013 in Copenhagen, Denmark, the biggest tattoo festival in Northern Europe. During the three days, 180 of the world's best and most celebrated national and international tattoo artists show the audience their skills in making art on the body and tattoo's on the audience. (Photo by Lars Krabbe/AP Photo)

A passenger plane comes into land over a field containing horses at Heathrow Airport on August 11, 2014 in London, England. Heathrow is the busiest airport in the United Kingdom and the third busiest in the world. The airport's operator BAA wants to build a third runway to cope with increased demand. (Photo by Peter Macdiarmid/Getty Images)

A boy runs past one of the exhibits during the Dinosaurs exhibition in Belgrade, Serbia, Thursday, August 21, 2014. “Dino Park” has opened at Belgrade's Kalemegdan Fortress. (Photo by Darko Vojinovic/AP Photo)

A person tries to extinguish flames as sparks fly during a wild forest fire in Valparaiso, Chile, Sunday April 13, 2014. Authorities say the fires have destroyed hundreds of homes, forced the evacuation of thousands and claimed the lives of at least seven people. (Photo by Luis Hidalgo/AP Photo)

Fisherwomen laying barrels with salt in preparation for herring curing, 1937. (Photo by Topical Press Agency)