Alghero is a good example of the need for a good defence system against the many enemy invasions that have taken place over time.  The fortifications built in the past are still partly visible.  The demolition of the walls as a consequence of the approval of town planning regulations, began with the pulling down of the large fortresses at the end of the 1800s, and continued into the early 1900s.  Despite the drastic reduction in the walls and towers, it is still possible to follow paths that come together to provide important details about the history of Gothic Alghero.