A snowflake rests on black velvet after a snowfall in Knoxville on Tuesday, January 28, 2014. (Photo by Adam Lau/News Sentinel)

A general view showing the shipwrecked cruise ship Costa Concordia in an upright position after the salvage operations in Giglio island, Italy, 17 September 2013. Salvage crews pulled off a major engineering feat when they straightened the listed Costa Concordia cruise ship from the rocks it had been wedged against for the past 20 months. The delicate operation took 19 hours and was completed at 4 am (0200 GMT). The vessel ran aground near the island of Giglio, in Tuscany, in an accident that made world-wide news. (Photo by Angelo Carconi/EPA)

Austrian artist Erwin Wurm (R) stands next to an extra of his participation sculpture “Hose lueften, Haende hoch” (air out pants, hands high) at the garden of the Staedel Museum, in Frankfurt am Main, Germany, 06 May 2014. The series “Wurm: One Minute Sculptures” include painted or written instructions tell the person what they have to do and where for 60 seconds. The exhibition runs from 07 May to 13 July. (Photo by Arne Dedert/EPA)

Two workers shovel mud from the river as they look for gold on March 25, 2014 in Lampang, Thailand. Thai villagers from Wang Nuea, North of Thailand, look for gold in the river every year during the drought season. They are able to make an average around USD 15 per day, however two years ago they reached USD 200 in one day due to the river level dropping so much. The workers begin to search for gold at 10 AM and work until sunset, often working second jobs in the day in order to survive. (Photo by Borja Sanchez-Trillo/Getty Images)

A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)

Reuters photographers Carlos Barria and Bobby Yip photographed protestors and details of life on the barricades, asking demonstrators what their role was in the movement, and what they wanted to happen. Here: Crystal, 15, a part-time boutique sales assistant, poses on Nathan Road in Mongkok shopping district in Hong Kong October 7, 2014. Holding a walkie talkie for fast communication with other supporters, Crystal said, “I am not demanding Chief Executive Leung Chun-ying to quit, but (want) to protect protesters from being threatened badly by opponents and the police”. (Photo by Bobby Yip/Reuters)

A model of the New Horizons spacecraft is seen at a live television program on NASA television celebrating the spacecraft's closest proximity to Pluto, at Johns Hopkins University Applied Physics Laboratory, site of the mission operations center, in Laurel, Maryland, USA, 14 July 2015. At approximately 7:49 am ET (11:49 am GMT), 14 July, New Horizons was scheduled to be as close to Pluto as the spacecraft will get; about 7,800 miles (12,500 kilometers) above the surface, following a journey of more than nine years and three billion miles. This is the first mission to the Pluto System and the Kuiper Belt. (Photo by Michael Reynolds/EPA)