Fodor's Expert Review Castell de Sant Ferran

Just a minute's drive northwest of Figueres is this imposing 18th-century fortified castle, one of the largest in Europe—only when you start exploring can you appreciate how immense it is. The parade grounds extend for acres, and the arcaded stables can hold more than 500 horses; the perimeter is roughly 4 km (2½ miles around). This castle was the site of the last official meeting of the Republican parliament (on February 1, 1939) before it surrendered to Franco's forces. Ironically, it was here that Lieutenant Colonel Antonio Tejero was imprisoned after his failed 1981 coup d'état in Madrid.

Call ahead and arrange for the two-hour Catedral de l'Aiguas guided tour in English (€15), which includes a trip through the castle's subterranean water system by Zodiac pontoon boat.