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)

Journalists interview a girl, member of the Cryophile amateurs winter swimmers club, after bathing in the ice waters of the Yenisei River, during the celebrations for the upcoming Christmas and New Year, in Krasnoyarsk, Russia, December 23, 2017. (Photo by Ilya Naymushin/Reuters)

These men are chased by the defiant elephants on May 4, 2013. Taken by Biplab Hazra in Bishnupur, India, the images show the extreme lengths the inhabitants of the town go to to deter elephants from damaging their crops and property. Elephants encroaching out of their habitats is an increasingly common occurrence with deforestation in much of India. (Photo by Biplab Hazra/Caters News Agency)

Shoppers walk past crocodiles for sale at a market in Bata on February 3, 2015. Markets in Equatorial Guinea sell a variety of animals including pangolins, monkeys and crocodiles as food. (Photo by Carl de Souza/AFP Photo)

Ballet dancer Anoushka Zoe James dances in the water at the Ipanema beach in Rio de Janeiro, Brazil on October 29, 2020. (Photo by Pilar Olivares/Reuters)

Festival goer with phallus logo t-shirt during the Kanamara Matsuri Steel Phallus Festival at Kawasaki, Japan on April 2, 2017. The Kanamara Matsuri or Festival of the Steel Phallus is held on the first Sunday of April at the Kanayama shrine. The shrine celebrates a legend of a steel pen*s and was frequented by prostitutes who wished to pray for protection from sexually transmitted diseases. Visitors now wish for easy delivery, marriage and matrimonial harmony. Because of the large steel phallus the unusual festival has become a tourist attraction attracting many overseas visitors and is used to raise money for HIV charities. Phallus shaped candy, carved vegetables, decorations, and a big parade are all part of the festival. (Photo by DELETREE/SIPA Press/Rex Features/Shutterstock)

A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

A group of people are seen on a Victoria line train in London, England during the first night of the Night Tube service on August 19 2016. The Central line and Victoria line are the first to operate a Night service with further lines expected to be running by the end of the year. (Photo by SWNS.com)