A competitor reacts as she 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)

Caroline Wozniacki of Denmark serves to Alisa Kleybanova of Russia during the BNP Paribas Open at the Indian Wells Tennis Garden on March 15, 2011 in Indian Wells, California. (Photo by Matthew Stockman/Getty Images)

People crowd onto 42nd Street as they take photos of the “Manhattanhenge” phenomenon in the Manhattan borough of New York July 11, 2014. Manhattanhenge, coined by astrophysicist Neil deGrasse Tyson, occurs twice a year, when the setting sun aligns itself with the east-west grid of streets in Manhattan. (Photo by Carlo Allegri/Reuters)

Girls of the Long Horn Miao ethnic minority group wear headdresses as they prepare gather for Tiaohua or Flower Festival as part of the Lunar New Year on February 6, 2017 in Longga village, Guizhou province, southern China. (Photo by Kevin Frayer/Getty Images)

King George V (1865–1936), king of Great Britain since 1910, with his queen-consort Queen Mary (1867–1953), at Collier Hospital on a visit to Dublin. (Photo by Topical Press Agency/Getty Images)

Handout grab taken from YouTube of Commander Chris Hadfield who has said goodbye to life on the International Space Station by making a cover version of David Bowie's Space Oddity. Issue date: Monday May 13, 2013. (Photo by Commander Chris Hadfield/YouTube/PA Wire)