Two stallions confront each other at a horse fighting contest in Rongshui, China. More than 30 horses from surrounding regions took part in the traditional activity of the Lantern festival. (Photo by China Foto Press)

Afghan air force 2nd Lt. Niloofar Rhmani walks the flight line at Shindand Air Base, Afghanistan, prior to her graduation from undergraduate pilot training, on May 13, 2013. Rhmani made history on May 14, when she became the first female to successfully complete undergraduate pilot training and earn the status of pilot in more than 30 years. She will continue her service as she joins the Kabul Air Wing as a Cessna 208 pilot. (Photo by Senior Airman Scott Saldukas/USAF)

Final match Soccer Humanoid Kid Size between DARwIn vs. AUTMan at the World Championship finals of RoboCup 2013 in Eindhoven (NL). (Photo by Bart van Overbeeke)

Tony Appleton, a town crier, announces the royal birth outside the Lindo Wing of St Mary's Hospital after Catherine, Duchess of Cambridge gave birth to a baby boy in central London July 22, 2013. Prince William's wife Kate gave birth on Monday to a baby boy, in the Lindo Wing of St Mary's Hospital, who becomes third in line to the British throne, his office said. The royal baby, the couple's first child, was born at 4:24 p.m. (15:24 GMT), weighing 8 lbs and 6 oz. (Photo by Lefteris Pitarakis/Associated Press)

A biker passes by a pair of mailboxes in the Capitol Hill neighborhood November 6, 2012 in Denver, Colorado. Colorado is considered by most experts to be one of the key battleground state in this year's presidential election. (Photo by Marc Piscotty/AFP Photo)

Burdened with a shawl full of her belongings, a woman stops for a rest on the road between Julaca and Puno in Peru. (Photo by Three Lions/Getty Images). Circa 1955

Lucie Clayton instructs pupils in the art of correct posture by balancing a glass and book on their heads at her finishing school in Old Cavendish Street, London. (Photo by William Vanderson/Fox Photos/Getty Images). 25th November 1936

These girls are scantily dressed as they head out for a night out in Portsmouth, Hampshire on September 21, 2016 in matching outfits. Thousands of Portsmouth University students enjoy freshers week. Teenagers enjoy their first taste of freedom in bars and clubs near Portsmouth Guildhall which on a midweek alcohol fuelled night of fun in the early hours of Wednesday morning much to the despair of local residents who get disturbed up to 4am when they eventually wander home. Girls dressed in “Dirty Disco” outfits with “Don't tell daddy” on their bums. (Photo by Paul Jacobs/PictureExclusive.com)