Bunkers are buildings designed to protect their inhabitants from an outside danger (super storms, war, doomsday scenarios, etc.). Bunkers may contain storage areas for food, water purification systems, ventilation shafts, entertainment centers, hydroponic gardens and more. They may have hidden entrances and exits, airlocks, or decontamination chambers. They may be built underground or within mountains. If designed for a large enough population, bunkers may more closely resemble bunker cities.