Aviation enthusiast Patrick Wilson 8, from Wetherby looks at an Avro 504 k at “The Shuttlesworth Collection” at Old Warden on July 21, 2014 in Biggleswade, England. Of the 55,000 planes that were manufactured by the Royal Army Corps (RAC) during WWI, only around 20 remain in airworthy condition. Six of these belong to The Shuttleworth Collection at Old Warden, Bedfordshire, making it the most complete collection of original airworthy WWI aircraft in the world. Amongst the collection is the SE5a. The SE5a is a single seater fighter aircraft. It is an original biplane designed by the Royal Aircraft Factory, with its engine built by Wolseley Motors Ltd, and it was issued to 84 Squadron in November 1918. The National Archive in Kew has recently verified that the plane saw action in France with 84 Squadron the day before Armistice, November 10, 1918. (Photo by Dan Kitwood/Getty Images)

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)

Rush-hour in Russia means one thing for this daredevil: train surfing! The 19-year-old daredevil who goes by the name Kobzarro started train surfing aged 15 as a way of escaping an oppressive family life. Here Kobzarro can be seen balanced on top of a train as it speeds through the wintery Russian environment. Kobzarro is so dedicated to train surfing that she rarely gets inside a train. Even in winter she prefers to travel in this less conventional way. It has resulted in a few run ins with the law, but Kobzarro says it has never resulted in anything more serious than a fine, with many police officers even being interested in the train surfing community. (Photo by Caters News Agency)

Storm chaser Brad Mack from Buena Park California videotapes a rotating supercell storm west of Newcastle, Texas April 9, 2013. Many of the storms in Tornado Alley that were forecast to be severe this week were taken out by a cold front from Canada. Picture taken April 9, 2013. (Photo by Gene Blevins/Reuters)

Aeronautics and Space engineer at France's Compagnie Maritime d'Expertises, or Comex, Arnaud Prost (C) meets with a jogger as he tests on the ground the “Gandolfi 2” underwater training suit for spacewalk, on January 20, 2016 in the calanques region (rocky inlets) of Marseille. The underwater training suit “Gandolfi 2”, developed with the European Space Agency (ESA), is designed for training astronauts underwater to simulate space gravity for the astronaut's extravehicular activities (EVAs). (Photo by Boris Horvat/AFP Photo)

A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)

Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson/AFP Photo)

Mongolia's Olympic wrestler Battsetseg Soronzonbold (front) fights with her training partner during a daily training session at the Mongolia Women’s National Wrestling Team training centre in Bayanzurkh district of Ulaanbaatar, Mongolia, July 1, 2016. Battsetseg Soronzonbold became a national hero in her native Mongolia after winning wrestling bronze at the London Olympics and is determined to turn the medal into gold in Rio next month. (Photo by Jason Lee/Reuters)