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 copy of part of the Dead Sea Scrolls is displayed at the “Dead Sea Scrolls: Life and Faith in Biblical Times” exhibition at Discovery Times Square on December 16, 2011 in New York City. (Photo by Spencer Platt/Getty Images)

A vendor sleeps as his son waits for customers at their roadside vegetable shop in New Delhi, February 12, 2019. (Photo by Adnan Abidi/Reuters)

Rani rides home with her father on the back of his bicycle on March 6, 2017 in Khulna division, Bangladesh. Rani, who is now 16, was under pressure to marry a boy when she was 14-years-old despite the reluctance of Rani and her father, Abdul. (Photo by Allison Joyce/Getty Images)

A boy sits on his father's shoulders to look at strawberries at the 7th International Strawberry Symposium on February 18, 2012 in Beijing, China. (Photo by Lintao Zhang/Getty Images)

Revelers dressed as Father Frost, the equivalent of Santa Claus, dance during a parade in Almaty December 28, 2014. (Photo by Shamil Zhumatov/Reuters)

Father Christmas reading with three young children. (Photo by Spencer Arnold/Getty Images). Circa 1915

Father Christmas hands out presents to children at the Aid And Adoption Society home at Leytonstone. (Photo by Gerry Cranham/Fox Photos/Getty Images). 7th December 1938