Starlings come home to roost on Brighton's Old Pier as the sun sets on December 21, 2011 in Brighton, England. December 21 marks the winter solstice, the shortest day of the year. (Photo by Dan Kitwood/Getty Images)

American singer-songwriter Chappell Roan performs during her “Midwest Princess Tour” at the Brixton Academy on September 21, 2024 in London, England. (Photo by Jim Dyson/Getty Images)

Swedish fashion model Elsa Hosk attends the “The History Of Sound” red carpet at the 78th annual Cannes Film Festival at Palais des Festivals on May 21, 2025 in Cannes, France. (Photo by Benoit Tessier/Reuters)

Axed Love Island stars Alima, Emily and Megan all went braless in very daring outfits last night, after appearing on Aftersun in London on July 21, 2025. (Photo by James Curley/The Sun)

Sophia Weisberg of Brazil competes on the balance beam during the 53rd Artistic Gymnastics World Championships in Jakarta, Indonesia, October 21, 2025. (Photo by Dita Alangkara/AP Photo)

An air tanker flies low over a wildfire burning on the edge of the Cariboo region city of Williams Lake, British Columbia, Canada on July 21, 2024. (Photo by Spencer Stratton/Handout via Reuters)

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)