Pakistani students look out from a vehicle on their way to school near the Army Public School which was targeted by Taliban militants last year, in Peshawar, Pakistan, Monday, January 12, 2015. (Photo by B.K. Bangash/AP Photo)

Bikers push their motorbikes during a traffic block as they take part in the “Enduropale” motorcycle endurance race on the beach of Le Touquet, northern France, February 1, 2015. About 1100 motorbike and 600 quad bike riders descend on Le Touquet every year for the racing endurance event. (Photo by Pascal Rossignol/Reuters)

This picture taken on February 1, 2015 shows participants competing in a tofu (beancurd) wrestling competition in Fogang county, south China's Guangdong province. Participants, mostly women, fight it out in an inflatable pool which is filled with nearly two tons of fresh milk and tofu, in a promotion to attract tourists for the upcoming Chinese Lunar New Year holiday. The upcoming Chinese lunar new year of the sheep, which will fall on February 19 this year, marks the biggest festival of the year in China as hundreds of millions of people journey across the country to celebrate the season with their families. (Photo by AFP Photo/Stringer)

A gallery staff member walks past Fleeting Monument (1985) by artist Cornelia Parker, one of the works on display at Yorkshire Sculpture Parks Longside Gallery as part of the “Making It: Sculpture in Britain 1977-1986” exhibition on March 27, 2015 in Barnsley, England. (Photo by Christopher Furlong/Getty Images)

A woman smokes a mask bong on the final day of Hempfest, Seattle's annual gathering to promote the legalization of marijuana, on August 17, 2014. (Photo by Jordan Stead/Seattlepi.com)

Participants hang from ropes as they learn how to use safety gears at an experience centre for construction safety training in Beijing, September 5, 2014. The centre which opened in June 2014 was established to educate workers about construction safety. According to the centre, about 1,000 construction workers undergo 3-hour classes which comprises of 33 modules every month. (Photo by Kim Kyung-Hoon/Reuters)

Ten-year-old Macy Friday, front left, reacts as she looks back at her family after meeting Hillary Clinton, front right, as she campaigns for U.S. Sen. Mark Udall, D-Colo., back, during a stop in the newly-renovated Union Station in Denver on Monday, October 13, 2014. Clinton appeared at an event to raise money for Udall's current re-election campaign and then headed to Las Vegas for another appearance on Monday night. (Photo by David Zalubowski/AP Photo)

West Berliners crowd in front of the Berlin Wall as they watch East German border guards demolish a section of the wall on November 11, 1989. (Photo by Gerard Malie/AFP Photo)