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 new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

View of a group of ostriches, in the gardens of the Palacio do Alvorada, in Brasilia, Brazil, 02 June 2020. The ostrich is the largest and heaviest bird in the world. When the chicks hatch they are between 25 and 30 cm tall, weighing about 900 grams. (Photo by Joedson Alves/EPA/EFE/Rex Features/Shutterstock)

Australian surfer Sally Fitzgibbons rides a wave during the 2023 ISA World Surfing Games at the El Tunco beach in El Salvador on June 6, 2023. (Photo by Marvin Recinos/AFP Photo)

France's defender #07 Sakina Karchaoui (L) and France's forward #11 Kadidiatou Diani (R) celebrate their win at the end of the Australia and New Zealand 2023 Women's World Cup Group F football match between France and Brazil at Brisbane Stadium in Brisbane on July 29, 2023. (Photo by Dan Peled/Reuters)

The World Enduro Super Series roared back into life this weekend with Mario Roman coming out on top at the Toyota Porto Extreme XL Lagares on May 12 to stake an early claim for the title of Ultimate Enduro Champion 2019. The Spaniard beat the 300 competitors, including 50 pros, who entered Sunday's Hard Enduro feature race in the baking Portuguese heat. Here: Graham Jarvis and Billy Bolt race at Toyota Porto Extreme XL Lagares, Portugal on May 12, 2019. (Photo by Future7Media/Red Bull Content Pool via AP Images)

Union Berlin players celebrate after the Bundesliga playoff second leg match between 1. FC Union Berlin and VfB Stuttgart at Stadion an der alten Foersterei on May 27, 2019 in Berlin, Germany. (Photo by Annegret Hilse/Reuters)

The Arizona State Sun Devils cheer team performs during the second half of the NCAAF game at Sun Devil Stadium on September 01, 2022 in Tempe, Arizona. (Photo by Christian Petersen/Getty Images)