A man pours mud water on the head of his girl friend during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Friday, July 18, 2014. The annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

15-year old American girl Donica Streling meets with members of SHINee (샤이니) at SM Entertainment head office on June 20, 2012 in Seoul, South Korea. Donica, diagnosed with Charcot-Marie-Tooth disease, visited Seoul, South Korea to meet her favorite K-pop groups SHINee and Super Junior after finding hope in listening to Korean pop. (Photo by Chung Sung-Jun)

A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)

Catholic pilgrim Matilde Madalena de Jesus crawls on a rocky trail carrying a bottle of water on her head during the annual pilgrimage of the dead (Romaria dos Finados), in the city of Juazeiro do Norte, Ceara state, in Brazil October 31, 2016. (Photo by Ueslei Marcelino/Reuters)

Large waves break at Burleigh Heads on the Gold Coast,, Queensland, Australia, 05 June 2016. Recent wild weather unleashed heavy rainfalls, powerful winds and abnormally high tides in Southeast Queensland and northern New South Wales. (Photo by Dan Peled/EPA)

From London to New York! These action shots show talented athletes practising yoga poses in iconic city locations. The amazing snaps were taken by photographer Kristina Kashtanova at urban street locations in the UK and New York. The talented yogis are seen striking mind-boggling poses in the most unusual settings. Here: Yoga head stand, Brooklyn, New York. (Photo by Kristina Kashtanova/Caters News)

New York City policemen tangled with demonstrators at a subway station on the opening day of the New York World's Fair, April 22, 1964. Youths attempted to stall the train, which was headed from the city to the fairgrounds, as a form of protest on behalf of civil rights for blacks. (Photo by Charles Gorry/AP Photo)

It’s enough to make your head spin. The photographer Katherine Young set out to shoot spiral staircases in London, England to great effect, including this shot she calls the Downward Spiral Part III. (Photo by Katherine Young/Rex Features/Shutterstock)