Man walking in front of wall of solidified lava inside Algar do Carvao

man walking solidified lava lava tunnel wall volcano algar do carvao volcanic terceira azores volcanic cone extinct volcanic tube eruption rocks geology interior inside island portugal portuguese europe lava tube cave geological formations light shinning bright colorful geological stalactites underground path angra landmark sites of interest nature landform natural wonder attraction background hole tourist travel alone lone loneliness 4k