Revellers from Russia parade during the Aoussou Carnival in Sousse, Tunisia July 26, 2015. (Photo by Anis Mili/Reuters)

Tour guides wearing traditional Chinese dress practice smiling by biting chopsticks at Qingming Grand-River Park in Kaifeng, central China's Henan Province on March 2, 2017, aiming to provide better service for visitors. (Photo by IPA Asia via ZUMA Wire)

A sales woman of a fish shop shows king crabs to a customer and negotiates the price in Noryangjin Fish Market is seen on August 1, 2015 in Seoul, South Korea. Noryangjin Fish Market was established in 1927 as Gyeongseong Susan in Jung-gu near Seoul Station and moved to its current location in 1971. (Photo by Shin Woong-jae/The Washington Post)

Sculptures entitled “The Rising Tide” by British sculptor Jason deCaires Taylor are seen beside the River Thames in front of the Houses of Parliament and the London Eye ferris wheel in London, September 3, 2015. The representations of four horses and riders are fully visible at low tide but become immersed underwater twice a day as the Thames rises to reach full tide. The installation will be on display throughout September as part of the annual Totally Thames festival. (Photo by Toby Melville/Reuters)

Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Erotic members-only club Snctm in Los Angeles, California, USA on January 28, 2017. A masqued black-tie dinner that evolves over the course of the night from amuse bouche to what founder, Damon Lawner, calls “erotic theater”, where female performers. Some guests engage, some engage only with each other (while women can buy a ticket, men cannot attend unless they’re members ($10,000-$50,000), part of a couple, or reserve dinner), and others choose not to touch at all. The monthly event at a Holmby Hills mansion is not a sеx or swingers party, but instead is about exploring the boundaries of what sеx means, and how it inherently makes us all feel. (Photo by Elizabeth Lippman)

Horse riders perform with guns during the El-Jadida International Horse Show in El-Jadida, south of Casablanca, Morocco, October 15, 2016. (Photo by Youssef Boudlal/Reuters)

Competitors perform at the World Irish Dance Championship on April 13, 2014 in London, England. The 44th World Irish Dance Championship is currently running at London's Hilton London Metropole hotel, and will host approximately 5,000 dancers competing in solo, Ceili, modern figure choreography and dance drama categories during the week long event. (Photo by Dan Kitwood/Getty Images)