Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

American actress and model Megan Fox stuns in a lace crop top and matching stockings in Manhattan, New York as she strolled to a business meeting on September 12, 2021. (Photo by Rex Features/Shutterstock)

Visitors were able to pick their own flowers on this sunflower trail at Gloagburn Farm near Perth, in Scotland on September 13, 2021. Crawford Niven, a farmer, said he was inspired to make the trail, which is made up of nearly 200,000 plants, after seeing similar ones in America and Australia. (Photo by South West News Service)

(L-R) Miss Universe 2015 Pia Wurtzbach, Miss USA 2015 Olivia Jordan and Miss Teen USA 2015 Katherine Haik attend the 2016 Miss USA pageant at T-Mobile Arena on June 5, 2016 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

A young girl tries to catch snow on her tongue near the Martin Luther King Jr. Memorial, before the start of a wreath-laying ceremony honoring the legacy of the late civil rights leader in Washington, DC on January 15, 2024. The ceremony is being held to honor the civil rights leader on the anniversary of his birthday. (Photo by Andrew Caballero-Reynolds/AFP Photo)

World's Greatest Swimming Pools: Four Seasons, Serengeti Pool, Tanzania. A show of elephants, buffalo and baboons awaits thanks to an active watering hole below the free-form infinity pool at this plush hideaway inside Serengeti National Park. Bonus: Because of infrared technology at the hole, guests can be notified on their bedroom TV when animals are approaching. When you've got word of wildlife on the horizon, catch them from your private terrace – or head back to the pool. (From $1,650). (Photo by Four Seasons)