Ключевые слова: abandoned, attraction, bulgaria, carriage, cavern, coal, corporation, danger, dark, deep, dig, dirty, display, entrance, equipment, exhibition, exposure, heritage, historical, history, inactive, industrial, industry, long, mine, miner, mineral, mining, mountain, museum, old, ore, passage, pernik, rail, room, round, shaft, skirt, steel, tool, tunnel, underground, work,