Bison along the Bitterroot Valley's Eastside Highway north of Stevensville, Montana, are covered in snow following a blizzard on November 23, 2010. (Photo by Perry Backus/The Missoulian)

Two carnival revellers masquerade as Leonardo da Vinci's painting “Mona Lisa” pose in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. (Photo by Domenico Stinellis/AP Photo)

A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

The British rock and roll group the Beatles talk to Ed Sullivan at CBS Studio 50 before their live television appearance on “The Ed Sullivan Show” in New York, February 10, 1964. From left to right are, Sullivan, John Lennon, Ringo Starr, holding a cigarette, and Paul McCartney. (Photo by AP Photo)

A migrant carries his belongings as he arrives at the Beijing railway station to catch a train in Beijing, Friday, February 13, 2015. (Photo by Andy Wong/AP Photo)

A tourist catches snowflakes on her tongue during snow fall in Times Square, Midtown, New York, on January 3, 2013. A major snowstorm producing blizzard-like conditions hammered the northeastern United States on Friday, causing more than 1,000 U.S. flight delays and cancellations, paralyzing road travel, and closing schools and government offices. (Photo by Darren Ornitz/Reuters)

People take cover outside the Fort Lauderdale-Hollywood International airport after a shooting took place near the baggage claim on January 6, 2017 in Fort Lauderdale, Florida. Officials are reporting that five people were killed and 8 wounded in an attack by a single gunman. (Photo by Joe Raedle/Getty Images)

Dancers pose after performing “El Macho Raton”, “El Toro Huaco” and “El Gueguense” traditional dances during San Sebastian festivity in Diriamba, province of Carazo, some 50 km south of Managua on January 19, 2016. Devotees of Saint Sebastian dance in traditional costumes between the cities of Diriamba and Dolores, which are some three kilometers away. (Photo by Inti Ocon/AFP Photo)