Secret passages, also commonly referred to as
hidden passages or
secret tunnels, are hidden routes used for stealthy travel. Such passageways are sometimes inside buildings leading to
secret rooms. Others allow occupants to enter or exit buildings without being seen. Hidden passages and secret rooms have been built in castles and houses owned by heads of state, wealthy individuals and criminals. These passages have helped besieged rulers to escape from their attackers, including
Pope Alexander VI in 1494,
Pope Clement VII in 1527 and
Marie Antoinette in 1789. Passages and tunnels have been used by criminals, armies (notably the
Viet Cong in the
Vietnam War) and political organizations to smuggle goods and people or conceal their activities.