Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)

Two holidaymakers amuse themselves with a porter's trolley whilst waiting for their train at Euston Station, London, 5th August 1939. (Photo by A. J. O'Brien/Fox Photos/Getty Images)

Abigail Crouse lifts her Thor hammer high after running through Sleeping Beauty's Castle during the Avengers Super Heroes Half Marathon in and around the Disney Parks in Anaheim, California November 16, 2014. Walt Disney Co has moved aggressively into the race business, attracting tens of thousands of runners every year to its marathons, half-marathons and family-friendly races. (Photo by Eugene Garcia/Reuters)

Runners rest inside Kim Il Sung Stadium in Pyongyang, North Korea on Sunday, April 14, 2013. North Korea hosted the 26th Mangyongdae Prize Marathon to mark the upcoming April 15, 2013 birthday of the late leader Kim Il Sung. (Photo by Alexander F. Yuan/AP Photo)

A fishmonger prepares fresh festive seafood supplies at the Sydney Seafood Market on December 23, 2011 in Sydney, Australia. The annual 36-hour seafood marathon commenced today with thousands of Sydney shoppers expected to flock to the Sydney Seafood Market to find the freshest possible seafood catch for Christmas Day feasts. (Photo by Brendon Thorne/Getty Images)

A participant peeks from his costume before the start of the the annual London Pantomime Horse Race in Greenwich, Britain December 13, 2015. (Photo by Neil Hall/Reuters)

Clowns and entertainers gather to attend an annual service of remembrance in honour of British clown Joseph Grimaldi at All Saints Church in Haggerston in London, Britain, February 5, 2017. (Photo by Toby Melville/Reuters)

A woman lies injured after an incident on Westminster Bridge in London on Wednesday, March 22, 2017. A police officer has been stabbed near to the British Parliament and the alleged assailant shot by armed police. Scotland Yard report they have been called to an incident on Westminster Bridge where several people have been injured by a car. (Photo by Toby Melville/Reuters)