Son Doong - World’s Largest Cave
The Phong Nha-Ke Bang National Park in Vietnam contains the oldest karst system in Asia, between 400-450 million years old. Hang Son Doong (Son Doong Cave) itself is relatively young, with the analysis of sediment dating it to be only 3 million years old.
Formed on the edge of a fault zone, Hang Son Doong has been carved out by the mighty Rao Thuong River as it erodes away the limestone, forming the enormous tunnel beneath the Annamite Mountains. Giant sinkholes, known as dolines, have collapsed sometime up to 300’000 years ago, creating massive openings to the outside world. Cave pearls the size of baseballs have been formed by water dropping from the ceiling.