deer cave - gua payau or gua rusa in sarawak on borneo island, malaysia, gunung mulu national park, sedimentary rocks known as

wild underground travel tourist tourism swift stone speleology sarawak rusa rocky rock park outdoors nature natural mulu mountain miri malaysia limestone light large landscape karst jungle illuminate hole gunung guano gua green geology geologic formation exploration earth deer deep dark cockroach cavern cave borneo bat attraction asia ancient adventure payau island national sedimentary rocks nesting swifts bats living