A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)

Participants lay down on a street covered by coloured powder during the annual Bangkok Color Run in Bangkok, Thailand April 1, 2017. (Photo by Athit Perawongmetha/Reuters)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)

Gifts for the homeless are handed out during Santa Bar Crawl, Oxford, England on December 5, 2017. Here: Oxford university students on a Santa-themed pub crawl. (Photo by Greg Blatchford/Rex Features/Shutterstock)

People with a South Korean flag waves as fireworks get off outside the stadium during the opening ceremony of the Pyeongchang 2018 Winter Olympic Games at the Pyeongchang Stadium on February 9, 2018. (Photo by Martin Bernetti/AFP Photo)

Costumed characters participate in the 30th annual Dragon Con Parade in Atlanta, Georgia, USA, 03 September 2016. Thousands of attendees crowd downtown Atlanta hotels and streets during the Labor Day weekend for the Dragon Con science fiction and fantasy convention, many dressed as their favorite characters. (Photo by Erik S. Lesser/EPA)

People participate in a winter fishing event in Changchun, Jilin province, China, December 25, 2016. Picture taken December 25, 2016. (Photo by Reuters/Stringer)

Four-year-old Rashida from Kobani, Syria, part of a new group of more than a thousand immigrants, sleeps as they wait at border line of Macedonia and Greece to enter into Macedonia near Gevgelija railway station August 20, 2015. (Photo by Ognen Teofilovski/Reuters)