Fodor's Expert Review Base de Sous-Marins Keroman

Built by the Nazis during World War II, this submarine base is the world's largest 20th-century fort. Thirty submarines could be comfortably housed in the squat concrete bunker—and its 27-foot-thick roof withstood intensive Allied bombing virtually intact. Ninety-minute tours begin at noon and 3 pm daily in summer and during school vacations; they run at the same time on Sunday year-round. Call to find out when tours in English are scheduled.