Thien Duong is the most monumental and magnificent cave in the Phong Nha-Ke Bang area.
It was first discovered in 2005 by a local person and subsequently surveyed by the British Cave Research Association (BCRA) from 2005-2010.
The survey results announced in 2010, report the cave is 31.4km long and 30-100m wide with a height of 60-80m, making it is the longest dry cave in Asia. Its geological tectonics dated 350-400 million years.
The cave is located in Son Trach village, Bo Trach district, Quang Binh province, around 70km far from Dong Hoi City and 25km far from Phong Nha Cave. It lies in the limestone zone of the Phong Nha-Ke Bang National Park – a world’s nature heritage recognized by UNESCO.
It opened to visitors as from September 2010.