sentences:  The fortification was originally a stone fortress built on solid rock - in an irregular and indented layout, which consists of three parts, out of which the central core represents the oldest part of the castle.In the southeastern part of the core there was a high guard tower (nowadays in ruins), which is the only remaining original part of Ottokar castle.Just next to the guard tower lies a semicircular tower with a small gothic chapel of St. Ana which is estimated to be built in third decade of the 16th century.