Adventurer, cave explorer slash photographer Ryan Deboodt recently explored the 'Hang Son Soong' (Mountain river cave) in Vietnam. Now this is a cave that was only discovered by an local man in 1991, and proper scientific exploration started only about 5 years ago. Deboodt equipped himself with a drone and a handful of cameras and started exploring it. What followed, was nothing short of a fantasy trip.
And here's the footage that will give you a clue about how enormous the cave is.