The Castell de Sant Ferran is a fortress of staggering scale. Built between 1753 and 1766 under the orders of King Ferdinand VI of Spain, it covers nearly 32 hectares — making it the largest fortress in Europe by perimeter and one of the largest in the world. Its design, by military engineer Juan Martín Cermeño, combined the most advanced Baroque military engineering of the era: a polygonal trace with eight bastions, deep dry moats, counterguards, and an enormous internal cistern capable of supplying water to a garrison of 9,000 soldiers and 500 horses for up to a year.
The castle was built to defend the Pyrenean frontier with France — the low pass at the Coll de Pertús, through which invaders had entered Spain repeatedly throughout history. Paradoxically, its military history was largely one of surrender rather than resistance. French forces occupied it during the Peninsular War in 1808 and again in 1823. It served as a prison for much of the 19th century, holding republican and liberal prisoners during Spain’s turbulent political upheavals.
Sant Ferran’s most dramatic modern moment came in February 1939, when the Republican government held its last meeting on Spanish soil in the castle’s cisterns, just days before the fall of Catalonia to Nationalist forces. The politician Juan Negrín conducted the final session of the Republican Cortes here before the government fled into exile.
Today guided tours take visitors through the vast underground cisterns — which can be toured by kayak — the barracks, the officers’ quarters, and the extraordinary panoramic views of the Empordà plain and the distant Pyrenees.