Pint-sized Kasteel Radboud was built by Count Floris V in the 13th century and served as a prison before a 19th-century remodelling by Pierre Cuypers, who designed Amsterdam's Rijksmuseum. The original floor plan has been preserved and the imposing Ridderzaal (Knights' Hall) still looks much as it did in the Middle Ages. Interpretative signs (in English) detail the castle's long history and the count's undoing. It's signposted from the harbour on the eastern side of town. Admission includes an audioguide.
Falconry demonstrations take place in summer.