A lady smiles during the annual Calabar cultural festival in Calabar, Nigeria, December 28, 2015. Picture taken December 28, 2015. (Photo by Reuters/Stringer)

The chariot of God Bhairab is pulled through the city centre of Bhaktapur near Kathmandu during the Bisket festival April 10, 2015. The festival, which runs for more than a week and coincides with the Nepalese New Year, involves devotees offering prayers and the pulling of two chariots, one carrying the idol of God Bhairab and the other with the idol of Goddess Bhadrakali, around the ancient city of Bhaktapur. Devotees participate in the festival with the belief that they will be blessed with good health, fortune and harvest for the coming year. (Photo by Navesh Chitrakar/Reuters)

Ukrainian Air Force officers attend a graduation ceremony at the National University of Defence of Ukraine in Kiev, April 24, 2015. (Photo by Gleb Garanich/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)

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)