Ancient city walls of Avila, Spain.

In order to defend Spanish territory and resist the invasion of the Moors, the Spaniards built the city of Avila in the 11th century AD. The ancient city of Ávila is located on a cape on the right bank of Adaga, a tributary of the Douro River, adjacent to the old Castile Plateau. The Celts settled here two thousand years ago BC. The first Christian church was built in 65 AD during the Roman era. Historically, it served as a defensive function and was also a religious center and the capital of the province of Ávila. The city of Ávila still retains its medieval simplicity, which can be seen from its Gothic cathedral and its fortifications, which consist of 82 semicircular towers and 9 city gates. It is the most complete castle in Spain.