A new adventure tour to Son Doong, the world's largest cave, in Bo Trach District, Quang Binh Province, has attracted more than 160 tourists as of June 26, according to the provincial Department of Culture, Sports and Tourism.

Only a small number of tourists can visit the cave yet because the tour is organised only four times a month and for just eight people at a time, said the department.

The tour lasts seven days and six nights and costs US$3,000. Visitors have to book in advance online, but it is full-up until the end of 2016.

Next month the department plans to review the tour and its price to see if it can improve things.

The cave, situated in the Phong Nha-Ke Bang National Park, a UNESCO natural heritage site, is 200m high, 150m wide, and around 5km long. It has stunning giant stalactites, a large river, and a jungle with a diverse ecosystem inside. — VNS