This 10th-century castle, strategically located on the border between the kingdoms of Navarra and Aragón, is Javier's main attraction. Inside, there's a small museum dedicated to the life of San Francisco Xavier, the patron saint of Navarra, who was born here in 1506.

Xavier spent much of his life travelling, preaching, teaching and healing in Asia. Today his body lies in a miraculous state of preservation in a cathedral in Goa, India.