Locked Down Shot, HA, Daylight, view from up the city wall. Puerta del Carmen from outside the city walls. Alfonso VI ordered the construction of these fortifications after his conquest of Avila in 1090. 14 meters high and as much as 3 meters thick, these walls have about 90 towers and 9 entrance gates. The curious Espadana of Carmen was built over the gate of the city wall which bears the same name. Avila is a UNESCO World Heritage Site.