History, still standing:

A fortress in its own right, San Juan once was a western stronghold for Spain’s colonies. The San Juan National Historic Site includes much of the city’s 60-foot walls and the capitol’s three most popular landmarks – Castillo San Cristobal, Castillo San Felipe del Morro and Fortin San Juan de la Cruz, built in the 1600s and through the 1700s. As the site’s apex, and the primary point for military strategy to defend San Juan Bay, Castillo San Felipe del Morro towers to nearly 150 feet over the city. The lookout took more than two centuries to complete, as the Spanish continually sought to strengthen its foundation. Countless wars, including the Spanish-American War and World War II, took their toll on El Morro, but the landmark has been lovingly maintained. Kids and adults alike marvel at the casements and cannons, the restored lighthouse, the U.S. artillery fire control station and so much more. On the other side of the national site, Castillo San Cristobal keeps watch over the interior of the city and offers impressive views, including that of the fabled “Garita del Diablo,” the watch post from which soldiers are rumored to have simply vanished.