The wall encircling the town spans three periods – the first walls were constructed in the 8th century with the arrival of the Moors, and the second Muslim wall spans the 10th and 11th centuries (and onwards). The last (the majority of what you see), was constructed in the 17th century: Flemish Jesuit engineer Cosmander designed the formidable defences, adding moats, ramparts, seven bastions, four semibastions and fortified gates in the style of the famous French military architect the Marquis de Vauban.
To give an idea of the level of security: after crossing a drawbridge to get to the main gate, you come to a 150-sq-metre square, surrounded by bastions, turrets and battlements, a covered road and three lines of trenches, some of which are carved out of rock.
