dark, colorful textures of the walls in a lava tube of canaria island

dark colorful textures walls lava tube canaria island travel tunnel cave underground rock volcano volcanic geology inside park lighted light portugal portuguese porto judeu roofs textured speleology stone touristic wall background geothermal magma nature scenic terceira crack basaltic destination azores illuminated europe algar interior attraction cavern black caldeira guilherme moniz angra do heroismo aores coal deep carvao caving colorfultextures