Secret Passage - Appearance and Construction

Appearance and Construction

Secret passages often have hidden or secret back doors that are camouflaged so that they appear to be part of the fire wall, or so that they appear to be an architectural feature such as a fireplace, a built-in bookcase or another feature. Some entrances are more elaborately concealed and can be opened only by engaging a hidden mechanism or locking device. Other hidden doors are much simpler; a trapdoor hidden under a rug can easily conceal a secret passage.

Some buildings have secret areas built into the original plans, such as secret passages in medieval castles. Some medieval castles' secret passages were designed to enable the inhabitants to escape from an enemy siege. Other castles' secret passages led down to an underground water source, which provided access to water during a prolonged siege.

Traditional Arabic houses sometimes have a "Bab irr": a secret door used as an emergency exit built into the walls and hidden with a window sill or a bookcase. The name comes from one of the six gates cut through an ancient wall in Aden (in modern-day Yemen), which was opened only in the event of a state security emergency. In modern-day Spain, the Arab fortress of Benquerencia has a Bab al-Sirr known as the "Door of Treason."

Other secret passages have sometimes been constructed after the initial building, particularly secret tunnels. These tunnels have often been created as escape routes from prisons or prisoner-of-war camps, where they are known as escape tunnels. These secret tunnels typically require a hidden opening or door, and may also involve other deceptive construction techniques, such as the construction of a false wall. Other tunnels have been made for different reasons, such as smuggling tunnels used for smuggling firearms, illegal drugs, or other contraband.