Masonry walls fully encircled the city of San Juan by 1783, now Old San Juan, as part of a major system of fortifications that once defended the whole islet. It was considered one of the best fortified cities in the Caribbean. However, as with the rest of the fortified city, the construction of the approximately three miles of walls began with a small section and developed over many years.
If you take a stroll along the Paseo del Morro, you will notice that the natural cliffs that face the San Juan Bay to the west are massive enough to provide a great natural defense. However, in 1586, nearly 50 years after the construction of Castillo San Felipe del Morro began; rudimentary masonry walls were set above those cliffs at the Sana Elena and the San Agustín batteries. These walls served as improved lookout and defensive positions and immediately proved their worth when the Englishman, Sir Francis Drake, along with 27 ships and 2,500 men unsuccessfully attempted to take the fort in 1595.
However, after Sir George Clifford of Cumberland successfully attacked the fort from the east and held it briefly and the Dutch plundered and burned the city in 1625, Spain realized that the city and forts needed further fortification. Engineers Thomas O’Daly and Juan Francisco Mestre designed a “defense in depth” system which called for improvements to the walls and the construction of Castillo San Cristóbal.
They repaired the existing west walls and built and improved walls to the south and east to protect the city of San Juan. Bastions, angled structures that project outward, were added to the walls to provide additional reach and a better range of angles to fire cannon and muskets. Bastions also helped create confusion for would-be attackers. Finally, a wall connecting El Morro and San Cristobal was built along the rugged north coast and the city was entirely enclosed.
Five gates were built so that farmers, herders, soldiers and others could enter and exit the city. The San Juan Gate faced the bay and was the ceremonial gate used for dignitaries. There were two gates on the north side, one to the east and another facing the west. Each gate was protected by sentry boxes that sheltered the guards on watch.
All the planning, building and hard work paid off when in 1797, Sir Ralph Abercrombie, along with approximately 6,000 to 13,000 English and German attempted to take San Juan. The “defense in depth” concept was so successful that Abercrombie and his men never even reached the city and the forts gained the reputation as impregnable. The English never again mounted an attack against San Juan.
Life began to feel pretty safe in San Juan and the walls which protected the city began to feel like a trap for the residents that lived inside. The space inside was finite and there was no room for the construction needed by a growing population. The population grew so much that in 1897, most of the east wall was taken down, along with a portion of the south wall.
In the late 1890s, war with the United States was looming. Spain prepared by bringing additional cannons including the large Ordoñez. Some of the iconic “garitas” or sentry boxes were knocked down to provide a better range of vision and firing. But, the Spanish cannons were no match for the rifled guns of the U.S. ships and the centuries-old walls were not designed to withstand the impact of modern artillery shells.
In 1898, after the United States won the Spanish-American War, Puerto Rico became a U. S. territory and the walls, along with the forts were under U.S. Army jurisdiction. During the 1930s and 1940s, the walls were repaired and storm drainage was improved. Nine sentry boxes were reconstructed with concrete though the Army was criticized for not using historically authentic techniques and materials.
The U.S Army transferred jurisdiction of most of the remaining 2.5 miles of city walls to the National Park Service. These walls include many of the original features such as the bastions and sentry boxes or “garitas.” These walls range from 20 to 100 feet tall and some are between 50 feet wide at the base to 24 feet at the top. The San Juan Gate was restored with special attention to the historical significance of the fortified walls and today, skilled masonry workers preserve the remaining walls using almost the same techniques and materials as the Spanish did centuries ago.
Last updated: January 9, 2017