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)

Ravi Nath poses for a photograph with a cobra snake in Jogi Dera (Snake charmers settlement), in the village of Baghpur, in the central state of Uttar Pradesh, India November 10, 2016. An ancient tribe of snake charmers, known as Saperas, have thrived over the generations by catching venomous snakes and making them dance to their music. Snakes are revered by Hindus in India and snake charmers are considered the followers of Lord Shiva, the blue-skinned Hindu god who is usually portrayed wearing a king cobra around his neck. (Photo by Adnan Abidi/Reuters)

Assi Mbengue nibbles as she prepares for the start of Las Palmas' Carnival Queen ceremony in Las Palmas, Spanish Canary Island of Gran Canaria, February 24, 2017. (Photo by Borja Suarez/Reuters)

People walk past a sculpture entitled “Reunion” by artist Sam Jinks at a preview of the Melbourne Art Fair in Melbourne on August 1, 2018. The sculpture is made of silicone, pigment, resin and human hair. (Photo by William West/AFP Photo)

Richard Gamboa, dressed up as Santa Claus, walks in an alley of the slum Cota 905 during the “Santa en las calles” (Santa in the streets) event donating toys, food, and clothes in Caracas, Venezuela on December 1, 2018. (Photo by Marco Bello/Reuters)

Police run past a burning car as they push protesters back during the “yellow vests” demonstration near the Arc de Triomphe on December 8, 2018 in Paris France. “Yellow Vests” (“Gilet Jaunes” or “Vestes Jaunes”) is a protest movement without political affiliation which was inspired by opposition to a new fuel tax. (Photo by Chris McGrath/Getty Images)

Fashion fans pose outside the main catwalk venue during London Fashion Week Spring/Summer 2017 in London, Britain September 20, 2016. (Photo by Neil Hall/Reuters)

A Nepalese man sits outside a Hindu temple as a goat rests on a parked scooter in Khokana, Lalitpur District, Nepal, Monday, September 26, 2016. Writing on the wall offers prayers to Hindu god Shiva. (Photo by Niranjan Shrestha/AP Photo)