In the extreme north of the peninsula is the oldest working lighthouse in the world, dating from the first century. In the past, an outdoor ramp circled around its exterior. In 1790, Charles III changed it into an interior staircase when the building was restructured and gave its square shape. A listed UNESCO World Heritage Site, the 104m-high lighthouse, known as the Tower of Hercules, affords a panoramic view of the city and its coastline.