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 woman looks at the honour guard soldiers marching at the Tomb of the Unknown Soldier by the Kremlin wall, in downtown Moscow, on June 28, 2021. (Photo by Alexander Nemenov/AFP Photo)

“The Reward”. “A spot that a friend and I found that takes a bit of effort to get to. Needs the right swell and wind direction to come together for the backwash to really happen. We had been many times with OK results, but this morning everything lined up perfectly and I was rewarded with this split-second moment in time under some amazing morning light”. (Photo by Scott Harrison/2019 UK Surf Photo of the Year)

A cyclist rides in al-Qudra desert in the Gulf emirate of Dubai, on June 8, 2020. (Photo by Giuseppe Cacace/AFP Photo)

Ukrainian serviceman Valerii looks on at a position in a frontline, amid Russia's attack on Ukraine, in Mykolaiv region, Ukraine on October 26, 2022. (Photo by Valentyn Ogirenko/Reuters)

Ohio State drum major performs during the NCAA football game between the Ohio State Buckeyes and Notre Dame Fighting Irish at Ohio Stadium in Columbus on September 3, 2022. (Photo by Adam Cairns/USA TODAY Sports)

Lord Roscoe the cat runs through the crocuses on the lawns at the National Trust's 17th-century Ham House and Garden in Richmond, London on Monday, March 6, 2023. In recent years more than 500,000 bulbs have been planted to create a spectacle for visitors and to attract bees, butterflies and other pollinating insects. (Photo by Kirsty O'Connor/PA Images via Getty Images)

Visitors gather outside Ark Encounter, a 100 million USD, 510-foot-long re-creation of Noah's Ark in Williamstown Kentucky, USA, 05 July 2016. Ark Encounter is the brainchild of Australian-born creationist Ken Ham; it was built with the help of state tax incentives and the sale of 62 million USD in junk bonds. (Photo by Jim Lo Scalzo/EPA)