A mass pillow fight in Trafalgar Square in central London on April 5, 2014 on International Pillow Fight Day. (Photo by Jane Scanlan)

Children stand in a boat at the banks of the polluted Yamuna River during a dust haze as they wait to give a ride to worshippers in New Delhi during World Environment Day June 5, 2010. (Photo by Reinhard Krause/Reuters)

A participant wearing Kokoshnik, the Russian traditional headwear, walks out of the water during winter swimming festival in the town of Podolsk, south of Moscow, Russia January 5, 2017. (Photo by Maxim Shemetov/Reuters)

A trader weighs tobacco at a market in el-Fasher, in North Darfur February 5, 2015. Tobacco is one of the North Darfur war zone's main cash crops. (Photo by Mohamed Nureldin Abdallah/Reuters)

A giant storm cloud can be seen in the sky above swimmers near Mollymook Beach, south of Sydney, March 5, 2014. (Photo by David Gray/Reuters)

A boy runs next to a portrait of Thailand's King Bhumibol Adulyadej, placed in celebration of the King's 88th birthday, in Bangkok, Thailand, December 5, 2015. (Photo by Jorge Silva/Reuters)

Cameron Shonnard backflips a jump at Squaw Valley in Olympic Valley, California, December 5, 2015. An El Nino is forecasted for California, and regular precipitation has been welcomed after years of drought. (Photo by Max Whittaker/Reuters)

Female soldiers with their faces painted in the colours of the Venezuelan flag, march during a military parade to celebrate the anniversary of Venezuela's independence in Caracas, July 5, 2015. (Photo by Jorge Dan Lopez/Reuters)