phong nha ke national park / vietnam, 16/11/2017: group of cavers taking a break inside the hang tien cave in the phong nha ke

adventure asia bang beauty black caing cave cavern chamber dark exciting experience exploration explore hang jungle light mountain national nha outdoor oxalis park phong rainforest river rock scramble shadow southeast spectacular stalactite stalagmite thrill tien tour tourism tourist travel trip undergound vietnam wall water