People are seen at Avalon Beach on December 18, 2020 in Sydney, Australia. A cluster of Covid-19 cases on the northern beaches of Sydney has grown to 28, prompting NSW health officials to urge residents of affected suburbs to stay home. Traffic at Sydney Airport has increased as people rush to leave the city with several states imposing quarantine restrictions for New South Wales residents. (Photo by Jenny Evans/Getty Images)

Policemen escort a Femen activist who broke into a rally of Franco's dictatorship regimen followers in Madrid, Spain, 28 March 2021. (Photo by Zipi/EPA/EFE)

On Dale A. Browne’s first trip to Yellowstone, he “got the best shot” he’d ever taken after chasing this weasel for 30 minutes. The trip for the 58-year-old from Manassas, Va., was a gift from his wife and an opportunity to improve his photography skills with the help of guide and professional photographer Tom Murphy. (Murphy did not assist in the taking of this photo). (Photo by Dale A. Browne)

A fireball erupts from a 16-inch gun on the battleship USS Wisconsin during a live fire exercise in the Persian Gulf, October 13, 1990. The ship is in the Gulf as part of Operation Desert Shield. (Photo by John Gaps III/AP Photo)

People walk under Australia's iconic landmark Harbour Bridge in Sydney on April 3, 2019, as heavy fog blankets the city. Low visibility due to heavy fog affected traffic in the city and caused flight delays at the Sydney airport. (Photo by Saeed Khan/AFP Photo)

The silhouette of a woman is reflected in a puddle as she crosses a square in front of the Peter and Paul Cathedral in Saint Petersburg on March, 17, 2019. (Photo by Olga Maltseva/AFP Photo)

Galagos, more commonly known as bush babies, are tiny African primates with remarkable jumping abilities. Thanks to the elastic energy stored in the tendons of their lower legs, small-eared galagos can jump 6 feet straight up in the air. (Photo by Traer Scott/Chronicle Books)

“Strike Through The Mothership”. Every May for the last 3 years I have driven down to Tornado Alley to capture some amazing storms. This supercell held so much promise to drop a tornado but one small shift in the atmosphere and all that it produced was an extreme lightning show. Photo location: Broken Bow, Nebraska. (Photo and caption by Vanessa Neufeld/National Geographic Photo Contest)