Tam Thanh cave, Lang Son, Vietnam, Indochina, Southeast Asia, Asia

travel destination photography horizontal colour image asia indoors southeast asia indochina vietnam vietnamese culture lang son tam thanh cave cave geology natural landmark bright light illuminated rear view full length one person men walking adventure exploration railing dark shadow rock rock formation colour color inside interior tourist destination travel landmark place of interest typically vietnamese traditional culture tradition traditional traditionally vietnamese traditionally vietnamese south east asia southeast asian south east asian