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)

Kristina Elekes, 23, races on her ski during the Bikini Race contest held at Arena Platos Paltinis winter resort, near Sibiu city, 275 Km north from Bucharest, Romania, 06 March 2016. Bikini Race is a timed show on the slopes, at the fourth edition, for women dressed only in swimmsuits and some winter accessories. (Photo by Mihaela Bobar/EPA)

A girl reacts as coloured water is thrown on her face while celebrating Holi, the Festival of Colours, in Mumbai, India, March 13, 2017. (Photo by Shailesh Andrade/Reuters)

A woman cleans her boat after a snowfall in Srinagar, December 13, 2019. (Photo by Danish Ismail/Reuters)

Evangelia Platanioti of Greece competes in the Solo Technical Routine at the Glasgow 2018 European Synchronised Swimming Championships, Glasgow, Britain, 06 August 2018. (Photo by Neil Hall/EPA/EFE)

Sun Rongchun, 57, exercises with an improvised cervical traction device attached to a high bar at a sports complex in Shenyang, Liaoning province, China on April 9, 2019. (Photo by Sheng Li/Reuters)

An official (R) measures the size of a whale shark (Rhincodon typus) carcass on the shore of Teluk Betung beach in West Sumatra, Indonesia, 08 October 2019. The dead whale shark washed ashore at Teluk Betung beach on 07 October 2019. (Photo by Rajo Batuah/EPA/EFE)

Protesters shout as they hit a pole during ongoing anti-government protests in Beirut, Lebanon on November 19, 2019. (Photo by Andres Martinez Casares/Reuters)