Son Doong among top awe-inspiring caves around the world

Tall enough to house a 40-story skyscraper and long enough to fit a full New York City block, Son Doong Cave is so spacious that a 747 could comfortably fly through. This cave, located in Phong Nha Ke Bang National Park in central Vietnam, was only discovered in 2009, and is now regarded as the world’s largest. Its size is nearly unbelievable, but even more enchanting is the cave’s very own biosphere, complete with surreal “indoor” clouds and a jungle-system blanketing the floor.