|Built on top of a rock in the pass between the Bucegi and the Piatra Craiului Mountains, the fortress was used to protect Brasov against Turks and later served as a customs house. The castle has four towers. The oldest tower, Powder House Tower, houses the Cannon's Gallery and the Gunner's Room. During the 15th century, the Observation Tower and Eastern Tower were added. In 1622 the Gate Tower was added, a Polish attic was attached and the south curtain wall was tickened up to 3,5m (11ft.) thick. More renovations took place in 1723 and in 1883.