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)

Spanish MotoGP rider Joan Mir (R) of Team Suzuki Ecstar and other MotoGP racers ride mini electric motorcycles at a fan event at Twin Ring Motegi in Motegi, Japan, 17 October 2019. The event was held ahead of the MotoGP race of Japan's Motorcycling Grand Prix scheduled for 20 October 2019. (Photo by Toru Hanai/EPA/EFE)

Muslims pray at the top of Mount Al-Noor during their Umrah Mawlid al-Nabawi “Birthday of Prophet Mohammad” in the holy city of Mecca, Saudi Arabia January 16, 2016. Muslims believe Prophet Mohammad received the first words of the Koran through Gabriel, at the top of Mount Al-Noor in the holy city of Mecca. (Photo by Amr Abdallah Dalsh/Reuters)

In his series of untitled photographs Nobody Claps Anymore, the Mexican-American photographer Alec Dawson portrays ordinary people in their homes in a downbeat, ultra-stylised manner. Staring into space as they watch TV or water the garden, the real-life subjects of photographer hint at vast reserves of boredom and regret. (Photo by Alec Dawson)

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)

Icelandic horses walk in their paddock at a stud farm in Wehrheim near Frankfurt, Germany, as the sun rises Tuesday, June 1, 2021. (Photo by Michael Probst/AP Photo)

Crews inflate hot air balloons during the 39th annual New Jersey Lottery Festival of Ballooning at Solberg Airport Friday, July 29, 2022, in Readington, N.J. The festival, which runs through Sunday, July 31, will feature as many as 100 balloons. (Photo by Julia Nikhinson/AP 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)