It doesn’t matter from which direction you approach El Morro (501 Calle Norzagaray, Old San Juan, 787/729-6777, daily 9 a.m.–6 p.m. Dec.–May, daily 9 a.m.–5 p.m. June–Nov., $3 adults, $5 for both forts, $2 seniors over 62, free for children under 16, English tours at 11 a.m. and 3 p.m.), it’s an impressive sight to behold.

From San Juan Bay, which it was constructed to protect from attack, it’s an awesome feat of engineering and a daunting display of military defense featuring four levels of cannon-bearing batteries that rise 140 feet from the sea. From Old San Juan, the approach is more welcoming, thanks to an enormous expanse of grassy lawn and breathtaking views of the shore. It’s easy to see why this is such a popular spot for kite-flyers.

Inside El Morro is a maze of rooms, including gun rooms, soldiers’ quarters, a chapel, turreted sentry posts, and a prison connected by tunnels, ramps, and a spiral stairway. The foundations for El Morro were laid in 1539, but it wasn’t completed until 1787.

El Morro successfully endured many foreign attacks by the English in 1595, 1598, and 1797, and by the Dutch in 1625. During the Spanish-American War, the United States fired on El Morro and destroyed the lighthouse, which was later rebuilt.