Designed to protect one of the narrowest passages of the Aspe Valley since the early 19C, Portalet Fort is built on the hillside. It has become a historic landmark because the Vichy Regime used it as a prison for political figures between 1941 and 1945, among whom Léon Blum, Édouard Daladier, Georges Mandel and Marshal Pétain, who all spent time in this austere edifice.