Ключевые слова: abandoned, adit, ancient, artificial, calcite, catacomb, cave, cavern, corridor, creepy, danger, dark, deep, dig, disused, dungeon, exploration, formation, geological, geology, hall, industrial, inside, interior, large, limestone, maze, mine, mineral, mountain, mystery, nickel, old, ore, passage, prospecting, quarry, quartz, region, rock, sandstone, scary, speleo, speleology, stone, tunnel, tver, underground,