An exclusive adventure tour into Vietnam's Son Doong Cave, the largest in the world, is opening for bookings for 2016 and will accept only 500 tourists.
Oxalis Adventure Tours, the sole tour organizer permitted to enter the cave, said that Quang Binh Province authorities allowed it to continue organizing tours to the cave in 2016.
The company will have to maintain the same itinerary and number of tours, with a maximum number of 500 tourists in total, the company said.
Accordingly, each tour last for five days and four nights with ten people at most.
In 2016, the cave will open from January – August as usual to avoid bad weather.
Oxalis, headquartered in Phong Nha Ke Bang National Park in Quang Binh Province, has been organizing tours to Son Dong Cave since August 2013.
An exclusive tour needs about 25 people, including porters, a cooker, a tour guide, two cave experts and two park rangers.
The company is selling tours to the cave in 2016 on its website for about VND66 million (US$3,000) per person.
Tourists are required to make sure that their health is suitable for activities that include 50 km (31 miles) jungle and mountain trekking, elevation change up to 400m (between road and valleys), surface river crossing: 40 times (knee deep, 10-50m wide river), 10 km caving including rope climbs, rocky terrain and scrambling, 80m descent with rope and harnesses, underground river-strong current crossing and 5 days and 4 nights in caves.
Son Doong, which is 150 meters high and 200 meters wide, became known worldwide in 2009 when it was explored by members of the British Cave Research Association led by Howard Limbert and his wife Deb Limbert, guided by local resident Ho Khanh.
Oxalis often sold out limited tours well before it started. Tours in 2015 had been sold out in July 2014.