Near Augustus' statue, a small part of the original Roman wall is preserved. It enclosed the city and protected it from siege until the Middle Ages. Zaragoza's wall was 3km long. The first wall the city had was built in first century but was modified in the third century due to the uprisings of northern nations. It was between 4-5m wide and had 7m towers every 14m. The Roman wall had four gates which closed the main streets: Cardo and Decumanus.