Hot-air balloons float over the Oka River during the Russian Sky International Balloon Festival in Ryazan Region, Russia on July 26, 2021. (Photo by Alexander Ryumin/TASS)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

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)

Capybaras bathe in the hot spring water at the Saitama Children's zoo in Higashi Matsuyama city, Saitama prefecture on December 25, 2013. 13 capybaras in the zoo, originally from South America, enjoyed the hot spring water. (Photo by Toshifumi Kitamura/AFP Photo)

The sea leopard. The Antarctic Peninsula. (Photo by Paul Nicklen)

David Hall’s photographs of scenery and creatures off the coast of Canada in the Pacific Northwest portray serenity under the water, which belie the extreme challenges he faces to get his images. For each shoot, Hall wears a dry suit, a neoprene body suit that covers all of his body but his head and traps air inside to keep him warm. Water temperature in Canada’s British Columbia typically ranges between 45 and 50 degrees Fahrenheit. Photo: Moon jellyfish and cross jellies. (Photo by David Hall)

A Filipino woman wears a mask to try and protect against the spread of coronavirus in Malate district, Manila City on March 24, 2020. The Philippines has taken drastic measures to combat the spread of Covid-19. The entire country is under strict quarantine and the army is on the streets to monitor compliance. According to official figures, there are 462 positive cases and 33 dead in the Philippines, but it is thought that thousands of cases remain undetected due to lack of resources in a country where millions of people have no access to health care. In the poorest and most crowded areas, it’s almost impossible to adhere to the physical distancing required during quarantine. (Photo by Alejandro Ernesto/The Guardian)

A sculptor walks past ice sculptures at the Snow and Ice Sculpture Festival “Eiswelt Mainz” in Mainz, Germany, November 22, 2016. (Photo by Ralph Orlowski/Reuters)