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)

Soldiers evacuate a hostage from a mass shooting scene at the Terminal 21 shopping mall in Nakhon Ratchasima, Thailand, 09 February 2020. According to media reports, at least 21 people were killed, and as many as 30 wounded after a Thai soldier, identified as 32-year-old Jakraphanth Thomma, went on a shooting rampage with a M60 machine gun in the city of Nakhon Ratchasima, also known as Korat. Thomma held an unknown number of people hostage within the Terminal 21 shopping mall for around 17 hours before being shot and killed in a police operation. (Photo by Rungroj Yongrit/EPA/EFE)

Kanphitcha Sungsuk, 21, (C), lines up with young men to speak to officers during an army draft held at a school in Klong Toey, the dockside slum area in Bangkok, Thailand, April 6, 2017. Thailand is widely seen as a paradise for gay and transgender people, but many complain of being treated as second-class citizens and the obligation to respond to the draft can be a nightmare when they turn 21. (Photo by Athit Perawongmetha/Reuters)

Pedestrians stop to look at and photograph a DeLorean Motor Company DMC-12 customized to look identical to the car used in the film "Back to the Future Part II" and that will be part of a Lyft promotion in New York, October 21, 2015. In the 1989 movie, main character Marty McFly traveled to the future to October 21, 2015. (Photo by Lucas Jackson/Reuters)

Topless protesters from the organization PETA (People for the Ethical Treatment of Animals) stand with “banderillas” filled with red powder as about 100 people rally in front of the town hall square in Pamplona, Navarra, northern Spain, demonstrating against the treatment of fighting bulls in the Fiesta de San Fermin, 05 July 2017. The renowned eight-day festival made famous by Ernest Hemingway's 1926 novel “The Sun Also Rises” has running-with-the-bulls and a bullfight each day for the fair, which begins at noon on 06 July 2017. (Photo by Jim Hollander/EPA)

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)