A passenger takes off his pants as others not wearing pants dance while waiting for a subway train during the “No Pants Subway Ride” in Mexico City, Mexico, February 21, 2016. The event is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Carlos Jasso/Reuters)

Mamoni Mandal, member of the Rapid Action Force (RAF), attends a training session at a police training school in Kolkata April 15, 2007. (Photo by Parth Sanyal/Reuters)

An Indian underprivileged bride gets her jewellery adjusted by a relative during a mass marriage ceremony in New Delhi, India, March 10, 2016. Fourteen underprivileged couples tied up the nuptial knot in the mass marriage ceremony organised by various social organisations. (Photo by Rajat Gupta/EPA)

A tow car for the children's “Grand Prix” races which take place in a parking lot in Livonia, Michigan a suburb of Detroit, circa 1955. (Photo by Three Lions/Getty Images)

Two drunk race-goers make their way home after the last race of the third day of the Royal Ascot horse racing week June 19, 2003 in Ascot, England. (Photo by Scott Barbour/Getty Images)

An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) emerges from a cloud created when it broke the sound barrier in the skies over the Pacific Ocean, July 7, 1999. (Photo by John Gay/US Navy)

A Bull Frog hops around as Carlos Costly #13 of Honduras brings the ball up against the USA at Sun Life Stadium on October 8, 2011 in Miami Gardens, Florida. (Photo by Marc Serota/Getty Images)

During the spring harvest season, a group of traditional Malaysian honey hunters travel to the rainforest near the Thai border to collect honeycombs from giant bees – and risk their lives climbing 200ft trees. Here: Bees are sensitive to light, which makes them follow the glowing embers down to the ground. (Photo by Hasnoor Hussain/The Guardian)