Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A young performer cries as she parades during the Bun Festival on Cheung Chau island in Hong Kong Tuesday, May 6, 2014. Bun Festival, the Taoist God of the Sea, is worshipped and evil spirits are believed to be scared away by loud gongs and drums during the procession. The celebration includes bun scrambling, parades, opera performances, and children dressed in colorful costumes. (Photo by Kin Cheung/AP Photo)

Kendall Jenner seen at Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler on Sunday, January 8, 2017, in Beverly Hills, Calif. (Photo by Eric Charbonneau/Invision for Focus Features/AP Images)

Actress Tang Wei poses at the “Wu Xia” portrait session during the 64th Annual Cannes Film Festival on May 15, 2011 in Cannes, France. (Photo by Andreas Rentz/Getty Images)

Australian actor Chris Hemsworth (L) and Spanish model Elsa Pataky (R) attend the Governors Ball during the 96th Annual Academy Awards at Dolby Theatre on March 10, 2024 in Hollywood, California. (Photo by Mike Coppola/Getty Images)

Actress and model Charlotte McKinney attends the grand opening of NightSwim at Encore Beach Club at Wynn Las Vegas on May 5, 2017 in Las Vegas, Nevada. (Photo by David Becker/Getty Images for Wynn Las Vegas)

People wearing Christmas hats bath in a pool of watermelon peel during a Christmas service at a hot spring in Luoyang, Henan province, China, December 24, 2016. (Photo by Reuters/Stringer)

Melanie Chisholm, Emma Bunton, Melanie Brown and Geri Horner of the Spice Girls in concert at Wembley Stadium in London on Sunday, June 16, 2019. (Photo by Andrew Timms/PA Wire)