Phong Nha Cave · Big Enough to Hold a Whole Street

The cave system of Phong Nha–Ke Bang is one of the longest in the world, and its largest chamber is tall enough to hold a passenger aircraft.

The cave has its own clouds and its own river, and old passages cut off by groundwater. Survey teams who slept inside recorded the phenomenon that “the first man hears the water first”.

The rule for entering is that you must go with a guide. Local people say it is no rarity for people to be lost in this cave — further in, echo and direction are of no use.

Natural Mysteries / Quang Binh · Vietnam / Modern day