The Phong Nha-Ke Bang Tourism Centre has built a 30 metre, partially-artificial cliff at the gate of Hang Toi (Dark Cave), the highest of its kind in the country. 

The route will later be used as an adventure entertainment option for tourists.

Hang Toi is a part of tours of the national park, offering visitors such attractions as zip-lining and cave mud-bathing.

Established in 2001, the Phong Nha-Ke Bang National Park is among the 238 most important ecological zones in the world. 

Covering 85,754 hectares, the park was recognised as a UNESCO geological and geomorphological World Natural Heritage Site in 2003. 

With the length of 7.7 kilometres, it boasts a system of 300 different caves and grottos which date back some 400 million years. Particularly, Son Doong, which was first explored in 2009, is considered the largest natural cave in the world.

Recently, the New York Times named Quang Binh as one of the most attractive destinations in Asia and the world’s 52 top must-go sites for 2014.