Several sights of interest line Rue de la Citadelle, including the Maison Arcanzola (Arcanzola House), at No. 32 (1510); the Maison des Évêques (Bishops' House), at No. 39; and the famous Prison des Évêques (Bishops' Prison), next door to it. Continuing up you'll reach the Citadelle itself—a classic Vauban fortress built between 1625 and 1627, now occupied by a school. The views from the top, complete with maps identifying the surrounding heights and valleys, are panoramic.
Rue de la Citadelle, St-Jean-Pied-de-Port, 64220, France