The squat, star-shaped fortress crowning Montjuïc has a darker history than its panoramic terraces suggest. Built and rebuilt from the seventeenth century onward, its guns were aimed inward at Barcelona as much as outward at the sea, and the castle was used for centuries as a military prison and place of execution. The Catalan president Lluís Companys was shot here in 1940 on Franco's orders, and a plaque marks the moat where political prisoners were killed.
Today the fortress is a public space, reached by a cable car that swings up over the hillside gardens from the lower slopes. The views are the main reward: the whole sprawl of the commercial port directly below, the city stretching away to the Collserola hills, and the open Mediterranean beyond. The ramparts and the central courtyard are pleasant to wander, and changing exhibitions occupy some of the old barracks. Go for the outlook and the sea breeze as much as for the history.