A competitor in fancy dress emerges from muddy water during the Tough Guy Challenge endurance race on January 29, 2012 in Telford, England. Every year thousands of people run the 8 mile assault course which involves freezing temperatures, fire and ice. (Photo by Michael Regan/Getty Images)

Earlier this year, Belgian film-maker and artist Vincent Bal stumbled upon an uncanny resemblance to an elephant in the shadow of his tea cup. This gave him the idea for Shadowology, a series of doodles that interact with the shadows of simple, everyday objects: a banknote, some ice cubes and a flower, for example, can turn into a church, a woman and a hippy. “I draw a few lines and I get my image. It’s really the shadows that inspire me”, Bal says. Here: “Stonedog”. (Photo by Vincent Bal/The Guardian)

Zahra Lari runs in a scene shot for the Nike Middle East ad campaign filmed in Dubai, UAE, February 10, 2017. An online commercial released by Nike (NKE.N) this week that showed Arab women fencing, boxing and spinning on ice-skates has stirred controversy over its attempt to smash stereotypes about women leading home-bound lives in the conservative region. (Photo by Reuters/Nike)

Two women jump into a frozen pond as they compete in the Polar Plunge at Frozen Dead Guy Days in Nederland, Colorado March 14, 2015. The winter festival in the small mountain town commemorates the 1994 discovery of the corpse of Bredo Morstol, which is now housed in a shed on dry ice above the town. (Photo by Rick Wilking/Reuters)

Lisa Yu crawls through a mud pit under low slung barbed wire as she competes in The Tough Bloke Challenge on March 4, 2012 in Melbourne, Australia. The Tough Bloke Challenge is one of the most gruelling adventure runs in Australia consisting of 18 obstacles over a 6 km cross-country course laden with thick mud-pits and ice-cold water crossings. (Photo by Scott Barbour/Getty Images)

The World Bodypainting Festival held from July 4 to 6 at Lake Worthersee in Austria's southern Carinthia province included artists from around the world, drawing visitors to the “Mecca of Bodypainting”, according to the World Bodypainting Association. Photo: World Bodypainting Festival 2014. Photographed July 4th in Poertschach am Woerthersee, Austria July 4, 2014. (Photo by Jan Hetfleisch/Getty Images)

Sjinkie Knegt of Netherlands, left, and Park Se-Yeong of South Korea crash out as they compete in a men's 1500m short track speedskating final at the Iceberg Skating Palace during the 2014 Winter Olympics, Monday, February 10, 2014, in Sochi, Russia. (Photo by Bernat Armangue/AP Photo)

A Spanish recortador jumps over a bull during a show in Cali December 21, 2014. (Photo by Jaime Saldarriaga/Reuters)