This defensive wall system was built between the 16th and 18th centuries to protect the city and the Bay of San Juan, a highly strategic point in the Caribbean.

[6][7] The bartizans (garitas) found along the walls are considered emblematic of the city of San Juan and a symbol of historic heritage preservation in Puerto Rico.

[11][12] The remaining portions of the wall system are now historically protected, and it additionally consist of series of ramparts and bastions interconnected with El Morro and San Cristóbal defensive castles.

[13] The southeastern portion of the city wall system is the only section that does not remain as it was demolished by the end of the 19th century after suffering irreparable damages from the 1867 Virgin Islands earthquake.

During this time, the damaged southeastern portion of the wall was considered militarily redundant and physically obstructive for the eastward urban expansion of Old San Juan.

From here the wall extends southward by La Fortaleza, a former military palace that today serves as the main residence of the Governor of Puerto Rico.