A general view shows the part of the skyline of Dubai covered in an early morning fog on October 5, 2015. (Photo by Rene Slama/AFP Photo)

A woman sells vegetables near a Metro train station in downtown Lima, Peru December 1, 2015. (Photo by Mariana Bazo/Reuters)

Four-month-old fox cubs squaring up to each other in Walthamstow, England on August 7, 2015. (Photo by Greg Morgan/Barcroft Media)

Attendees at Wizard World Comic Con walk through hallways in Chicago, Illinois, United States, August 22, 2015. (Photo by Jim Young/Reuters)

A competitor participates in the Tough Mudder challenge near Henley-on-Thames in southern England May 2, 2015. (Photo by Eddie Keogh/Reuters)

A helicopter drops water over a wildfire as a firefighter works to contain it in Benahavis, southern Spain, May 19, 2015. (Photo by Jon Nazca/Reuters)

A participant smiles at the annual Christopher Street Day parade on Kurfuerstendamm in Berlin, Germany, June 27, 2015. (Photo by Fabrizio Bensch/Reuters)

A knight parades in the street during the traditional carnival parade in Cologne, western Germany, Monday, February 16, 2015. (Photo by Martin Meissner/AP Photo)