QUANG BINH (VNS)—Two seven-day/six-night tours, costing US$3,000 each, to the 5km-long Son Doong Cave in the central Quang Binh Province will begin this month.

In addition, three five-day/four-night tours will be held each month for $2,300.

After the trial period, if operations go well, adventure tours to Son Doong Cave will be organised from February to August every year.

The cave, located in Phong Nha-Ke Bang National Park, was first discovered by a group of British scientists in 1991.

According to British experts, it is five times larger than the nearby Phong Nha Cave, previously considered to be the largest in Viet Nam. Son Doong Cave is 200m wide and 150m high.-VNS