Marching around this noble stronghold is a riveting history lesson. Visitors scale stairs and stride across rampart walkways, peering into the 13th-century chapel and former cells. The prison was ironically nicknamed 'Himmelreich', the kingdom of heaven (to where its unfortunate prisoners would soon be dispatched). Find also time-smoothed gravestones and baroque statues though a few pieces (like the iconostasis) aren't originals. It's worth navigating the creaking stairs of the Flamboyant Gothic clock tower (reconstructed in 1777).
Choose between a guided tour (on the hour) or self-guided visit with a pamphlet in your chosen language.