Chinese aids activists hand out condoms in a subway train in Wuhan, central China's Hubei province on December 1, 2014. The World Health Organization issued a call to action to China on December 1, 2014 over HIV/AIDS as government figures said nearly half a million people are living with the disease or its precursor, with hundreds of thousands more thought to be undiagnosed. (Photo by AFP Photo)

An armed man gestures in front of the police headquarters in Slaviansk, April 12, 2014. At least 20 armed militants wearing mismatched camouflage outfits took over the police and security services headquarters in the eastern city of Slaviansk seizing hundreds of handguns. (Photo by Gleb Garanich/Reuters)

Yaroslav Segeda at the top of a high rise building in Kudrinskaya Square, Moscow, Russia. (Photo by Yaroslav Segeda/Caters News)

A stuntman performs in a car at the “Well of Death” at an exhibition in Srinagar, India, Friday, May 23, 2014. In the Well of Death, stunt drivers on motorbikes and cars drive in circles around the vertical walls of the well-shaped construction. (Photo by Dar Yasin/AP Photo)

“Two Brothers”. We found about 20 lions eating a buffalo. When the male leaved the group we anticipated him to take photos. It is 8AM, light is perfect and the position too. The lion stops and looks down from the hill, another lion is coming up, it stiffens, I think that will be a fight, i'm tense, the camera is OK, the shots previously made perfect. The two meet, looking directly into their eyes, they sniff, rub against their heads, the tension drops, they start walking with the same step as when they were puppies, they are two brothers. Photo location: Masai Mara, Kenya. (Photo and caption by Massimo Mei/National Geographic Photo Contest)

This picture taken on July 15, 2014 shows a bridge submerged in floodwaters in the ancient town of Fenghuang, central China's Hunan province. Rainstorms lashed central China's Hunan Province and southwest China's Guizhou Province, affecting over 1 million people and flooding a historical town, state media reported. (Photo by AFP Photo)

Collided passenger train cars are seen in Taebaek, South Korea, Tuesday, July 22, 2014. Two passenger trains collided head-on in eastern South Korea on Tuesday afternoon, killing one passenger and injuring dozens, fire officials said. (Photo by AFP Photo/Yonhap)

Opossums on their mothers back at a game reserve in Central Minnesota, USA, on September 2, 2013. (Photo by Caters News Agency)