Horse riders perform with guns during the El-Jadida International Horse Show in El-Jadida, south of Casablanca, Morocco, October 15, 2016. (Photo by Youssef Boudlal/Reuters)

An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)

A swimmer disguised as Superman dives into the lake during the 78th “Coupe de Noel” (Christmas cup) swimming race in the Lake Geneva, on December 18, 2016 in Geneva. More than 1800 participants took part in the event, a 12-meter-long swimming off the Geneva's bank in the 7 degrees Celsius cold water. (Photo by Fabrice Coffrini/AFP Photo)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

A P-51 Mustang named “Charlotte's Chariot” from the Southern Heritage Air Foundation flies past a cloud of smoke and fire from a nearby battle reenactment during the Wings Over Houston Airshow in Houston, on Saturday, November 1, 2014. Battle reenactments are part of the yearly show held at Ellington Airport. (Photo by Kar Hlava/AP Photo/Bay Area Citizen)

A monkey is led by its trainer Qi Defang during training for a circus in Suzhou, Anhui province, November 29, 2014. Suzhou is known as the hometown of circus troupes in China and has more than 300 circus troupes. (Photo by William Hong/Reuters)

Dancers audition for a post as cheerleaders of the Miami Dolphins, in Rio de Janeiro, Brazil, Thursday, March 3, 2016. Brazilian dancers audition in the first international cheerleader recruitment for the Miami Dolphins in Rio de Janeiro. The Dolphins will also hold auditions in Colombia, Argentina, Mexico and South of Florida. (Photo by Felipe Dana/AP Photo)

Rugby Union, New Zealand vs Tonga, IRB Rugby World Cup 2015 Pool C, St James' Park, Newcastle, Englandon October 9, 2015: Fans is fancy dress before the game. (Photo by Andrew Yates/Reuters)