From the tower ran a series of tunnels to the outlying guardhouses. Access was controlled at seven security gates equipped with wooden guardhouses. After the war, one of the guardhouses (#1) was converted into a museum. The false crossings consisted of signs, border stones, administrative buildings, and guardhouses. Originally there were six bridges, three aqueducts, eight guardhouses and numerous smaller canals. The ruins of the defenders' barracks and guardhouses are still there. Some guardhouses also function as jails. This consists of a central block, with two lateral pavilions that originally served as guardhouses. The gate and its two adjacent guardhouses have been listed with the Gibraltar Heritage Trust. There are also two guardhouses by the entrance of the tunnel to the main entrance. Two guardhouses and three concrete tower bases still be seen on the two main sites. These guardhouses keep security guards comfortable as well as secure. There are two guardhouses next to the Prince Edward's Gate.