Ключевые слова: abandoned, background, below ground, catacombs, claustrophobia, collapse, construction, danger, dangerous, dark, deep, digging, dungeon, earth, eerie, endless, engineering, estonia, geological, geology, gloomy, gold, grim, ground, industry, interior, light, limestone, mineral, mining, perspective, phosphate, phosphorite, rock, sandstone, scary, sedimentary rock, speleology, spooky, stone, subterranean, subterraneous, tunnel, tunneling, ulgase village, underground, underpass, wall, water, wet,