A wine cellar is a storage room for wine in bottles or barrels, or more rarely in carboys, amphorae, or plastic containers. In an "active" wine cellar, important factors such as temperature and humidity are maintained by a climate control system. In contrast, "passive" wine cellars are not climate-controlled, and are usually built underground to reduce temperature swings. An aboveground wine cellar is often called a "wine room", while a small wine cellar (fewer than 500 bottles) is sometimes termed a "wine closet". The household department responsible for the storage, care and service of wine in a great mediaeval house was termed the buttery. Large wine cellars date back over 3700 years.