|Son Doong Cave in Vietnam’s central Quang Binh province. Photo: Internet.|
The New York City Drone Film Festival attracted 150 film entries from 19 countries.
Son Doong is in the UNESCO-recognised Phong Nha-Ke Bang National Park, Quang Binh Province. It is biggest known cave in the world, renowned for its unique eco-system.
The cave was found by a local man, Ho Khanh, in 1991 but was not properly explored until 2009, by a group of scientists from the British Cave Research Association, led by Howard and Deb Limbert revealed the cave was 150m wide, 200m high and more than 5km long.
In October 2014, local authorities allowed a Vietnamese company to survey the cave for building a 10km suspension cable to transport visitors, but work was suspended following public opposition. There were concerns that large numbers of tourists might damage the cave's ecosystem.
Good Morning America broadcast the report on May 13, 2015, to six million viewers. The film used a drone camera to show off the enormity of the cave and its natural beauty.
Millions of people have tried to book tours to see the cave after the film was broadcast but Oxalis Travel Co, the only tour company licensed to conduct trips to the cave, said that tours are booked out until the end of 2016.
A spokesman for Oxalis said more than 1,000 people had booked the five-day four-night tour, at a cost of USD3,000 a person.
Tours to Son Doong are restricted to 450 visitors a year.