Called “El Morro,” this fort stands on a rocky promontory dominating the entrance to San Juan Bay. Constructed in 1540, the original fort was a round tower, which can still be seen deep inside the lower levels of the castle. More walls and cannon-firing positions were added, and by 1787, the fortification attained the complex design you see today. Both the English and the Dutch attacked this fortress repeatedly.

The U.S. National Park Service protects the fortifications of Old San Juan, which, together, have been declared a World Heritage Site by the United Nations. With some of the most dramatic views in the Caribbean, you’ll find El Morro an intriguing labyrinth of dungeons, barracks, vaults, lookouts, and ramps. Historical and background information is provided in a video in both English and Spanish. The nearest parking is the underground facility beneath the Quincentennial Plaza at the Ballajá barracks (Cuartel de Ballajá) on Calle Norzagaray. Park rangers lead hour-long tours for free, although you can also visit on your own.

El Morro, along with Fort San Cristóbal (see below), forms the San Juan National Historic Site. Ancient underground tunnels originally connected the forts, but today two modern trolleys ferry visitors back and forth. The walk, however, is beautiful along the oceanfront Calle Norzagary. A museum at El Morro provides a history of the fort through exhibits of historic photographs and artifacts, written orientations, and a video presentation. A guided tour is offered hourly, but informational brochures allow you to walk around on your own while learning the story. There’s also a gift shop. Make sure to walk out on the northernmost point, a narrow wedge overlooking the waves crashing into the rocky coast. The promenade circling the base of the fort is also worth exploring. The grounds of El Morro are a great spot to fly a kite, and families and children are out every weekend doing so. An annual kite festival is also held every March. You can buy a kite at stands right in front of the fort, or at Puerto Rico Drug or Walgreens on Plaza Colón.