Son Doong Cave in Vietnam is one of the world’s largest caves. It has been open to the public since 2013.
This cave has two huge dolines and underground rainforests. It also has various unique cave formations.
Son Doong Cave is located in Phong Nha-Ke Bang National Park and Oxalis, a Vietnamese tour operator, leads Vietnamese research and tourist expeditions there in partnership with British Cave Research Association. More information is here.