An undercover police officer, who had been marching with anti-police demonstrators, aims his gun at protesters after some in the crowd attacked him and his partner in Oakland, California December 10, 2014. Police said more than 100 demonstrators marched in Berkeley, California, which has a history of social activism. Under cloudy skies, turnout was smaller than earlier in the week, when demonstrators in the area threw rocks at police and shut down a major freeway. (Photo by Noah Berger/Reuters)

The Kremlin's Spasskaya (Saviour) Tower, covered by scaffolding, is seen behind the mausoleum of Soviet state founder Vladimir Lenin at the Red Square in Moscow, December 23, 2014. The restoration works will last until the spring of 2015, according to local media. (Photo by Sergei Karpukhin/Reuters)

Ziripot, a traditional figure stuffed with straw, is helped up during Carnival celebrations in the Navarran village of Lantz, on February 16, 2015. (Photo by Vincent West/Reuters)

A painter was drawing a lion head body painting on a model during the auto show on March 15, 2015. The local 2015 auto show was held in Xuchang Stadium in Xuchang, Henan Province, China. The exhibitors tried a variety of ways for promotion and attracting people's attention. Some exhibitors were giving gifts to the people scanning their QR codes and add them onto friends list. An auto company has invited young s*x underwear models and drew body paintings on the girls. (Photo by Xu Zhongxin/Sipa Asia)

Chinese artist Zhou Jie takes a nap on an unfinished iron wire bed, one of her sculpture works, after lunch as a friend of hers looks on at Beijing Now Art Gallery, in Beijing August 11, 2014. Zhou started her art project titled “36 Days” on August 9, in which she would live inside an exhibition hall with an unfinished iron wire bed, some iron wire sculptures in the shape of stuffed animal dolls, a certain amount of food and her mobile phone, for 36 days. The entire process is open to visitors and she may also interact with them, according to Zhou. (Photo by Jason Lee/Reuters)

Te Matatini Kapa Haka Aotearoa perform the Haka at the Edinburgh Festival Fringe on the Royal Mile on August 14, 2014 in Edinburgh, Scotland. The largest performing arts festival in the world, this years festival hosts more than 3,000 shows in nearly 300 venues across the city. (Photo by Jeff J. Mitchell/Getty Images)

A picture made available on 17 September 2014 shows extreme athletes resting in hammocks on webbings stretched between rocks during the International Highline Meeting in Monte Piana, near Misurina, in the northern Italian Alps, Italy, 08 September 2014. (Photo by Balazs Mohai/EPA)

People look at home-made armoured vehicle look-alikes on a street in Shenyang, Liaoning province, November 12, 2014. A man surnamed Zhang and his friends converted two cars into these two vehicles, for his son, and will be displaying them on show at a local park. The cannons on the vehicles can fire paintballs and smoke shells, local media cited Zhang as saying. (Photo by Reuters/Stringer)