Old San Juan is a walker's paradise. Every callejon, street, is dotted with colors that will pop and at each corner of the small island is a fort, a castle. As you explore, churches rise to the sky, the ocean laps against its walls and its cats roam freely. This is truly a Caribbean paradise. Old San Juan is located on a small and narrow island which lies in the north coast, about 35 miles (56 km) from the east end of Puerto Rico, and is united to the mainland of Puerto Rico by the three bridges. It is bounded by the Atlantic Ocean to the north and to the south by San Juan Bay or "Bahia de San Juan" which lies between the city and the mainland.

For the explorers and the colonists of the New World who came from the east, Puerto Rico was an obligatory stopping-place in the Caribbean. From this evolved its primordial strategic role at the beginning of the Spanish colonization. The island was for centuries a stake disputed by the Spanish, French, English and Dutch. The fortifications of the bay of San Juan, the magnificent port to which Puerto Rico owes its name, bear witness to its long military history.

The San Juan National Historic Site was established in 1949 to preserve historic buildings and other fortifications in Old San Juan. The historic site was added to the National Register of Historic Places in 1966. La Fortaleza along with the San Juan National Historic Site were then declared a World Heritage Site by UNESCO (United Nations Educational, Scientific, and Cultural Organization) in 1983.