A girl plays with her pet goats at a village some 200 kilometers away from Kolkata, in Tumpa Mondal, India on July 21, 2019. (Photo by Tumpa Mondal/Xinhua News Agency/Barcroft Media)

Models play with a dog backstage at the Missoni Spring/Summer 2020 show during the Milan Fashion Week on September 21, 2019 in Milan, Italy. (Photo by Rex Features/Shutterstock)

A worker inspects the Christ the Redeemer statue which was damaged during lightning storms in Rio de Janeiro January 21, 2014. (Photo by Severino Silva/Reuters/Agência o Dia)

A boy runs past one of the exhibits during the Dinosaurs exhibition in Belgrade, Serbia, Thursday, August 21, 2014. “Dino Park” has opened at Belgrade's Kalemegdan Fortress. (Photo by Darko Vojinovic/AP Photo)

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)

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)