Safe rooms on civilian ships, sometimes called "citadels", are increasingly being installed as a countermeasure against piracy. When attacked, the crew can retreat into the safe room and call for help (which in the case of ships of some countries may include the intervention of military forces). Because of the nature of ship construction, the safe room is typically constructed in a concealed location within a void within the ship, to resist efforts by the pirates to find the crew before help arrives. Safe rooms sometimes have facilities to allow the crew to remotely disable the ship's engines and electronic systems, making it impossible for the pirates to sail the ship to a location they control. The safe room is also typically armoured against direct physical attack, to allow the crew to remain safe for a few hours, even if located by the pirates, and to allow rescuing forces full scope for the use of armed force to re-take the ship without risk to the crew.