High Quality Content by WIKIPEDIA articles! A safe (also called strongbox, coffer or kist) is a secure lockable box used for securing valuable objects against theft or damage. A safe is usually a hollow cuboid or cylinder, with one face removable or hinged to form a door. The body and door may be cast from metal (such as steel) or formed out of plastic through blow molding. It is often possible to open a safe without access to the key or knowledge of the combination; this activity is known as safe-cracking and is a popular theme in heist films. A diversion safe, or hidden safe, is a safe that is made from an otherwise ordinary object such as a book, a candle, a can, or even a wall outlet plug. Valuables are placed in these hidden safes, which are themselves placed inconspicuously (for example, a book would be placed on a book shelf).