This looks just like a fairy tale type castle, pointy turrets and all. Charles IV had this fortress built to house his crown jewels and religious artefacts in the 14th C. The Chapel of the Holy Cross has precious stones inlaid to the masonry and 129 paintings by Theodorik follow a fairly apocalyptic theme. Open Tue-Sun, 9am-6pm (Jul-Aug), 9am-5pm, (May-Jun and Sep), 9am-4pm (Apr-Oct), 9am-3pm (Nov-Mar), 200Kc, 100Kc students. Trains run from Praha Hlavni every hour.