An anti-government protester sits on the ground in front of police during a demonstration in Sarajevo February 6, 2014. Hundreds of people turned out in solidarity in the capital Sarajevo, with teenagers throwing eggs and stones at a government building and fought with police. Four officers were taken to hospital, officials said. (Photo by Dado Ruvic/Reuters)

In this February 2, 2014 photo, people take pictures inside a cave at Apostle Islands National Lakeshore in northern Wisconsin, which has been transformed into a dazzling display of ice sculptures by the arctic siege gripping the Upper Midwest. (Photo by Brian Peterson/AP Photo/Minneapolis Star Tribune)

In this Monday, March 10, 2014 photo, a 9,000 year-old mask is on display at the Israel Museum in Jerusalem. The exhibition called “Face To Face” shows eleven stone masks, said to have been discovered in the Judean desert and hills near Jerusalem, which date back 9,000 years and offer a rare glimpse at some of civilization's first communal rituals. (Photo by Tsafrir Abayov/AP Photo)

It might have been foggy in the Willamette Valley, but Cerridwen Martin was able to revel in a view of the top of the clouds from the summit of Spencer Butte in Eugene, Ore., on Tuesday, December 16, 2014. Martin was joined by Joe Martinson, right, for the 1.1 mile trek. Fog shrouded much of the city for most of the day. (Photo by Andy Nelson/AP Photo/The Register-Guard)

Two people sit in an ambulance waiting to be treated after a Grad rocket slammed into a shopping mall in Donetsk's Kubishevski district, in the eastern Ukraine, on October 8, 2014. At least two people were killed, and five were injured after some six Grad rockets hit the area. (Photo by John Macdougall/AFP Photo)

A female forest guard carries a tranquillizer gun in the Gir National Park and Wildlife Sanctuary in Sasan, in Gujarat December 2, 2014. The sanctuary, which is home to Asiatic lions in India, has an area of 1,412 sq km in which female guards were employed for the first time in India in 2007. The guards fetch a monthly salary of around $148 for working almost 12 hours a day, six days a week, said one of the female guards. (Photo by Anindito Mukherjee/Reuters)

A Zombie Santa is pictured Death Yard Haunted Attraction in Hendersonville, Tennessee December 10, 2014. The Nashville-area haunted house is getting into the Christmas spirit this weekend, with Zombie Santa, his undead elves and a demonic reindeer going on the attack for fun and charity. (Photo by Harrison McClary/Reuters)

A couple dances a tango in front of Saint Peter's basilica at the Vatican, December 17, 2014. At the rear edge of the square more than 2,000 people, who came to Rome from all over Italy for the 78th birthday of Pope Francis, danced in “A tango for Pope Francis” event as music blared. (Photo by Tony Gentile/Reuters)