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)

Jared Leto poses with fans for a selfie during the “Clear Channel Media and Entertainment” at the 2014 Cannes Lions on June 18, 2014 in Cannes, France. (Photo by Didier Baverel/WireImage)

French artist Christophe Guinet, also known as “Mr Plant”, works on his plant shoe creation “Wood”, part of the artistic project “Just Grow It”, in his art gallery in Marseille, November 25, 2014. Guinet transforms name-brand Nike sneakers, cult footwear for urban youth, into vegetable compositions, creating a collection of artwork with trainers modified with tree bark, foam and flowers. (Photo by Jean-Paul Pelissier/Reuters)

“El rio mas bonito del Mundo”, the most beautiful river of the world, the “River of five colors”, the “Rainbow River”, or even the “Escaped from Paradise”, are the shimmering appellations that Colombians give to Cano Cristales, a small stream located in the heart of the Macarena National Park, 150 km (93 miles) south of Bogota. Photo: A waterfall is seen at the end of the rainy season, in August, when the water level finally decreases, in the Cano Cristales RIver in the Sierra de la Macarena in Colombia. It has become covered with a bright pink endemic aquatic plant, Macarenia Clavigera. (Photo by Olivier Grunewald)

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)

An Iraqi man cooks traditional Masgouf fish on a barbecue for sale in the Karada market July 02, 2014. Masgouf, one of the national dishes of Iraq is a grilled carp seasoned with olive oil, rock salt, tamarind and ground turmeric. (Photo by Scott Nelson for the Washington Post)

Trick rider Kendel Sampson performs during the trick riding session of the RAM Rodeo in Warkworth, Ontario, on August 1, 2013. The teenage Encore Presentation Trick Riders perform daring stunts every rodeo season in towns throughout Canada. (Photo by Norm Betts/Barcroft Media)

Nuns react at the arrival of Pope Francis at the St. Mary's school to attend a meeting of clergy and religious in Nairobi, Kenya, 26 November 2015. Pope Francis is on a six days visit that will take him to Kenya, Uganda and the Repulic of Central Africa from 25 to 30 November. (Photo by Daniel Dal Zennaro/EPA)