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)

A young woman flashes the victory sign in front of a bonfire as Turkish Kurds gather during Newroz celebrations for the new year in Diyarbakir, southeastern Turkey, on March 21, 2018. Newroz (also known as Nawroz or Nowruz) is an ancient Persian festival, which is also celebrated by Kurdish people, marking the first day of spring, which falls on March 21. (Photo by Ilyas Akengin/AFP Photo)

A honor guard soldier stands at attention during a memorial religious service for those killed in the 1989 anti-communist uprising in University Square, in Bucharest, Romania, Wednesday, December 21, 2022. Participants and relatives of those killed marked the 33rd anniversary of the anti-communist uprising which started in Bucharest on Dec. 21, 1989 and left more than one thousand people dead and ended the rule of dictator Nicolae Ceausescu. (Photo by Andreea Alexandru/AP Photo)

Switzerland's forward #19 Eseosa Aigbogun (L) fights for the ball with Philippines' defender #16 Sofia Harrison (R) and Philippines' forward #21 Katrina Guillou during the Australia and New Zealand 2023 Women's World Cup Group A football match between the Philippines and Switzerland at Dunedin Stadium in Dunedin on July 21, 2023. (Photo by Sanka Vidanagama/AFP Photo)

The Bondi Icerbergs Pool was converted into a giant esky ice chest during the filiming of a Jim Beam commercial at Bondi Icebergs on March 21, 2013 in Sydney, Australia. (Photo by Marianna Massey)

A fan dressed as “Loki” poses before the European premiere of “Avengers: Age of Ultron” at Westfield shopping centre in Shepherds Bush, London April 21, 2015. (Photo by Stefan Wermuth/Reuters)

Activists from People for the Ethical Treatment of Animals (PETA) promoting a vegan diet are pictured as people drive past in Los Angeles, California May 21, 2015. (Photo by Mario Anzuoni/Reuters)