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)

The sun rises beside St Mary's Lighthouse in Whitley Bay, Tyne and Wear, as the unseasonably cool weather continues on Thursday, April 28, 2016. (Photo by Owen Humphreys/PA Wire)

A woman plays with her three dogs at the beach after sunset in Del Mar, California, USA on November 10, 2017. (Photo by Mike Blake/Reuters)

A pro-independence protester sits in front of Catalonia's regional parliament as lawmakers vote inside, in Barcelona, January 16, 2014. (Photo by Albert Gea/Reuters)

A hot air balloon floats past an almost full rising moon on a warm fall evening near Encinitas, California October 5, 2014. (Photo by Mike Blake/Reuters)

Women dance in costume during the West Indian Day Parade in Brooklyn, New York September 7, 2015. The parade, which takes place annually, celebrates Caribbean culture and history. (Photo by Andrew Kelly/Reuters)

A young woman jumps into the river Rhine to cool off during high temperatures, near Kaiserstuhl, Switzerland, Sunday, June 22, 2025. (Photo by Michael Buholzer/Keystone via AP Photo)

People stand in the middle of the graves and in front of giant kites in the cemetery of Santiago Sacatepequez, Guatemala, November 1, 2015. Dating back 116 years, the tradition of flying kites in the cemetery of of Santiago Sacatepequez, integrates the Catholic feast of All Saints with ancient Mayan practices of honouring the dead. It is believed that the kites connect the living and the dead during the all saints day celebration. (Photo by Jorge Dan Lopez/Reuters)