The majority of the fortifications surrounding Cádiz were constructed during the 17th century. Additional defenses were built for nearly another 100 years. The largest was Baluarte de San Carlos engineered by Antonio Hurtado. This huge, wedged-shape bastion dating from 1784 protected the northern harbor with a battery of up to 90 mounted cannons. Nine of the artillery are still aimed toward the bay. You can admire them as you walk along the crenelated Murallas de San Carlos (Walls of San Carlos).