basalt hexagonal columns close-up view on reynisfjara black sand beach, iceland

basalt beach black sand cave cavern ceiling cliff closeup column columnar empty erosion europe formation geology halsanefshellir hexagonal haiexcl lsanefshellir iceland icelandic inside landmark landscape lava mountain myrdal natural nature people outdoor pillar raw reynisdrangar reynisfjara rock shape shore south stack stone tourism travel vault vertical view vik volcanic wall