The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

This photo taken on August 7, 2016 shows mahjong enthusiasts playing mahjong under water in a swimming pool at a diving club in the Chinese city of Chongqing. Only participants with proper diving certification were allowed to take part in the underwater competition. (Photo by AFP Photo/Stringer)

A cosplayer poses for a photograph during the Comic Market 90 (Comiket) event in Tokyo Big Sight on August 12, 2016, Tokyo, Japan. Many manga and anime fans wearing cosplay lined up in the sun for the first day of Comiket. Comiket was established in 1975 and focuses on manga, anime, gaming and cosplay. Organizers expect more than 500,000 visitors to attend this year's summer event which runs for three days until August 14. (Photo by Aflo/Splash News)

Festival-goers wash on Shipyard Island, the venue of the 24th Sziget (Island) Festival in Northern Budapest, Hungary, 15 August 2016. The venue, one of the biggest cultural events of Europe, offers art exhibitions, theatrical and circus performances and above all music concerts from 10 to 17 August. (Photo by Szabó Gábor/Origo.hu)

An injured woman is pictured near the Blue Parrot nightclub in Playa del Carmen, Quintana Ro state, Mexico where 5 people were killed, three of them foreigners, during a music festival on January 16, 2017. A shooting erupted at an electronic music festival in the Mexican resort of Playa del Carmen early Monday, leaving at least five people dead and sparking a stampede, the mayor said. Fifteen people were injured, some in the stampede, after at least one shooter opened fire before dawn at the Blue Parrot nightclub during the BPM festival. (Photo by Victor Vargas/AFP Photo)

Contorsionist Rich Miteku performs during the opening of the 41st Monte-Carlo International Circus Festival in Monaco on January 19, 2017. (Photo by Valery Hache/AFP Photo)

A vervet monkey passes in front of a woman on the shores of lake Naivasha, Kenya January 24, 2017. (Photo by Goran Tomasevic/Reuters)

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)