A passenger without pants waits for the subway train during “The No Pants Subway Ride” in Mexico City January 11, 2015. The event, the fifth organized in Mexico, is an annual flash mob and occurs in different cities around the world, according to its organisers. (Photo by Edgard Garrido/Reuters)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

A swimmer competes during the UK Cold Water Swimming Championships at Tooting Bec Lido in south London January 24, 2015. (Photo by Luke MacGregor/Reuters)

Men eat oranges from a push cart along a road as a vehicle travels past them in Karachi January 22, 2015. (Photo by Akhtar Soomro/Reuters)

A man plays in front of a wave crashing into Beirut's Corniche, a seaside promenade, as high winds sweep through Lebanon ahead of an impending storm January 6, 2015. (Photo by Jamal Saidi/Reuters)

Competitors take part in the Red Bull Crashed Ice Cross Downhill World Championship in Marseille, France, January 14, 2017. (Photo by Jean-Paul Pelissier/Reuters)

Members of the Palestinian Hamas security forces show their skills as they take part in a graduation ceremony in Gaza City on January 22, 2017. (Photo by Mahmud Hams/AFP Photo)

School boys who attend Sri Lankan traditional dance training wait for their graduation ceremony at a Buddhist temple in Colombo, Sri Lanka January 23, 2017. (Photo by Dinuka Liyanawatte/Reuters)