Fort San Felipe del Morro (El Morro) was built on a promontory at the n.w. tip of Old San Juan, now part of San Juan National Historic Site. The grounds are closed to motor vehicles; visitors walk one-quarter mile (.4 km) to the fort from underground parking at Plaza del Quinto Centenario on Calle Norzagaray.
The most strategic of San Juan's defense systems, El Morro repelled attacks by the British, Dutch and French over the course of 300 years. Six levels of impressive batteries rising 140 feet (43 m) out of the sea afford a beautiful harbor view. A network of ramps and stairways connects the ramparts.
Construction began in 1539 with a simple tower designed to guard the channel to the harbor. Most of the massive earthworks and fortifications were built between 1589 and the 1650s, and the fort was completed by 1787. The fort contains a museum with examples of 16th- and 17th-century armor and weapons, a chapel and audiovisual exhibits.
Guided tours of the national historic site are available by reservation. Comfortable walking shoes are recommended.