Swiss rescue workers wheel a wounded person on a stretcher after two regional trains crashed head on near Granges-Pres-Marnand near Payerne in western Switzerland July 29, 2013. The two trains collided in the Swiss canton of Vaud on Monday evening, injuring about 40 people, four seriously, Swiss news agency ATS reported. There was no immediate report of any deaths in the crash. (Photo by Denis Balibouse/Reuters)

A woman dressed as the Star Trek character “Leeta” (C) and man dressed as “Rom” (2R) arrive to attend the “Destination Star Trek London” convention at the ExCeL centre on October 19, 2012 in London, England. The three-day convention, which opened to the general public today, will be attended by all five actors who played captains throughout the 46-year-old series. (Photo by Oli Scarff)

Labourers who work nearby nap on a road as cars drive past in Chongqing Municipality, July 23, 2013. (Photo by Reuters/Stringer)

A reveller is tossed into the air as they celebrate the Holi spring festival in Kathmandu on March 12, 2017. The “Holi” festival of colours is a riotous celebration of the coming of spring and falls on the day after the full moon in early March every year. (Photo by Prakash Mathema/AFP Photo)

North Korean commuters are seen through a door window waiting to board a train in a subway train station in Pyongyang, North Korea, 14 April 2017. North Koreans are preparing to celebrate the “Day of the Sun” festival, commemorating the 105th birthday anniversary of former supreme leader Kim Il-sung on 15 April, as tension over nuclear issues rise in the region. (Photo by How Hwee Young/EPA)

Taking it all in at Trolltunga, a piece of rock which juts horizontally out of a mountain, 700 metres above lake Ringedalsvatnet in Norway. (Photo by Sam Rogers/GuardianWitness)

Dancers perform on stage during Diwali celebrations in Leicester, Britain November 11, 2015. (Photo by Darren Staples/Reuters)

The "Skylanders Eruptor" balloon moves by people on balconies during the 89th Macy's Thanksgiving Day Parade in the Manhattan borough of New York, November 26, 2015. (Photo by Andrew Kelly/Reuters)