A competitor participates in the Tough Mudder challenge near Henley-on-Thames in southern England May 2, 2015. (Photo by Eddie Keogh/Reuters)

Guo Meiling of China jumps her Mini into the road during the 38th Dakar Rally in Arrecifes, Argentina, January 2, 2016. (Photo by Reuters/Stringer)

Opossums on their mothers back at a game reserve in Central Minnesota, USA, on September 2, 2013. (Photo by Caters News Agency)

People participate in a Zombie Walk in Sao Paulo, Brazil, November 2, 2016. (Photo by Nacho Doce/Reuters)

The Perseid Meteor Shower seen over The Scorhill Stone Circle in Dartmoor, Devon on August 2, 2016. (Photo by John Baker/SWNS.com)

The Lamb National takes place for the racegoers at Ascot Racecourse on April 2, 2017 in Ascot, England. (Photo by Alan Crowhurst/Getty Images)

Men work on a large hookah at the Taha factory in Baghdad, Iraq July 2, 2016. (Photo by Khalid al Mousily/Reuters)

A man sleeps at Beirut's Corniche, a seaside promenade, in Lebanon May 2, 2016. (Photo by Alia Haju/Reuters)