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 Vietnamese cosplayer poses as police officer character from the game during the League of Legends (LOL) Mid-Season Invitational 2019 play-in group stage, in GG Stadium, Ho Chi Minh, Vietnam May 5, 2019. (Photo by Reuters/Kham)

A Russian-made rifle, carried by this woman when she was captured in Nearby Brush, is slung around her neck by South Vietnamese soldiers before they began their interrogation of her as Viet Cong suspect near AP La Ghi in Vietnam, August 25, 1965. The girl behind the woman, also was captured in the brush. (Photo by AP Photo)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

Belgium's Davina Philtjens comforts Italy's Manuela Giugliano sitting on the ground at the end of the Women Euro 2022 group D soccer match between Italy and Belgium at the Manchester City Academy Stadium, in Manchester, England, Monday, July 18, 2022. Belgium won 1-0 to advance to the quarterfinals. (Photo by Jon Super/AP Photo)

A few revellers brave the cold and rain in Leeds, United Kingdom for the friday night out on December 30, 2022. Brits have kicked off their New Year’s Eve celebrations early with wild nights out up and down the country. (Photo by Nb press ltd)

Dancers perform inside of transparent balls during the Botanical Night at Botanical Garden in Berlin, Germany, 20 July 2018. During the Botanical Night a 16 kilometre long path along the flower beds and several themed gardens are illuminated and guide to many attractions. (Photo by Hayoung Jeon/EPA/EFE)

Thomas Shelby makes a fire as he prepares to stay the night by the rubble of his home to protect from potential looters in Dawson Springs, Kentucky, on Saturday, December 11, 2021. One or more tornados tore through Dawson Springs late last night. (Photo by Austin Anthony/The Washington Post)