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)

Japan's Naomi Osaka returns the ball during her match against Slovakia's Dominika Cibulkova during the Madrid Open tennis tournament, Sunday, May 5, 2019, in Madrid, Spain. (Photo by Andrea Comas/AP Photo)

A handout picture provided by the Vatican Media shows Pope Francis holding a flag of Ukraine that was sent to him from the Ukrainian town of Bucha during the weekly general audience in the Paul VI Audience Hall, in Vatican City, 06 April 2022. The pontiff lamented the “massacre of Bucha”, in the Kyiv suburb where dozens of bodies in civilian clothing have been found, and renewed his calls for an end to the war in Ukraine. (Photo by Vatican Media Handout/EPA/EFE)

Sap runs out of a frankincense tree near Mader Moge, Somaliland, a breakaway region of Somalia on August 4, 2016In a tradition dating to Biblical times, men rise at dawn in the rugged Cal Madow mountains of Somaliland in the Horn of Africa to scale rocky outcrops in search of the prized sap of wild frankincense trees. (Photo by Jason Patinkin/AP Photo)

A member of Sisters of the Valley, a non-religious international group founded in 2014 which has pledged to spread the gospel of the healing powers of cannabis, who uses the moniker “Sister Bernardet” online and asked not to give her name for fear of reprisal, smokes a joint at the Sisters of the Valley's farm on the outskirts of a village in central Mexico on September 3, 2023. (Photo by Raquel Cunha/Reuters)

A zoo staff feeds crocodiles as visitors look on at the Malabon Zoo in Malabon City, north of Manila, Philippines 21 December 2017. Wearing Santa Claus hats for the upcoming Christmas season, owner Manny Tangco (R, holding megaphone) and some select animals gave visitors a tour of the 28-year-old zoo. (Photo by Rolex Dela Pena/EPA/EFE)

One of the Houston Rockets NBA basketball team’s cheerleaders — known as the Power Dancers – in action during a game against the New Orleans Pelicans at Toyota Center on March 19, 2023 in Houston, Texas. The Rockets won 114-112. (Photo by Thomas Shea/Reuters)

A bunker at aformer Swiss artillery fortress called Heldsberg stands near the town of St. Margareten, Switzerland March 22, 2015. Heldsberg fortress, located on the Swiss-Austrian border near the River Rhine and Lake Constance was built from 1938 to 1940 and remained in military use until 1992. Since 1993 it is open to the public as Fortress Museum Heldsberg. (Photo by Arnd Wiegmann/Reuters)