Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft in this March 2, 2010 file photo. (Photo by Reuters/NASA/JPL/SSI)

A camel herder removes the rope from the mouth of a camel at the Pushkar Fair in Rajasthan, India, November 22, 2015. Thousands of animals, mainly camels, are brought to the annual fair to be traded. (Photo by Jitendra Prakash/Reuters)

A Macedonian police officer hits a stranded migrant attempting to cross the Greek-Macedonian border, near Gevgelija, Macedonia December 2, 2015. Picture taken from the Greek side of the border. (Photo by Alexandros Avramidis/Reuters)

Aerial Emery trains on the cyr wheel at the Aloft Loft circus training and teaching school which was converted from a church, in Chicago, Illinois, U.S., September 20, 2016. (Photo by Jim Young/Reuters)

A Belarussian border guard checks a passenger's passport in a train after it arrived from Lithuania, at the railway station Gudogai, Belarus, November 22, 2016. (Photo by Vasily Fedosenko/Reuters)

Firework display from the top of the Sky Tower to welcome the New Year on January 1, 2015 in Auckland, New Zealand. (Photo by Dave Rowland/Getty Images)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

Men eat oranges from a push cart along a road as a vehicle travels past them in Karachi January 22, 2015. (Photo by Akhtar Soomro/Reuters)