The mighty fortress walls in the old city of Avila have stood motionless for over 900 years. Not only local residents but also famous Moorish architects were involved in the construction. The work took 9 years, and the result was a high 12-meter wall stretching for 2.5 km. The walls of Avila are the best preserved of their "brothers", and in size they are second only to the Great Wall of China.