(No.3, Vol.6,Apr-May 2016 Vietnam Heritage Magazine)
Inside Hung Ton Cave
Tan Hoa, Minh Hoa,
Quang Binh Province
(from the 2016 Tu Lan Challenge discovery tour, organized by
Oxalis. 100 participants explored
30km of rivers, waterfalls, fields and vaiours caves over a
two- day period).
Photo: Thanh Vuong