Jutting out above the Tavignano and Restonica Rivers, and the cobbled alleyways of the Haute Ville, the citadel’s oldest part is the château – known as the Nid d’Aigle, meaning ‘Eagle’s Nest’ – built in 1419. The 19th-century barracks now houses the tourist office and the Museu di a Corsica, a must-see for Corsica culture buffs. It’s a joint admission for the museum and citadel.