The Roman Walls which once surrounded Córdoba, Spain, were built after the Romans captured the city in 206 BC, making it part of the Roman Republic.
Built as fortifications soon after the Romans captured Córdoba, the walls stretched some 2,650 m, completely surrounding the city. They consisted of carefully cut stone with an outer wall of up to 3 m high and a 1.2 m inner wall flanking a gap 6 m wide filled with rubble. There were several semicircular towers along the walls. When the city received the status of Colonia Patricia under Augustus, the southern wall was demolished in order to extend the city limits to the river. Vestiges remain in the Alcázar, near the Roman bridge, and flanking the Avenida de la Ribera. The walls next to Calle San Fernando and Calle Cairuán (restored in the 1950s) also have a base from this period. A section of the Roman wall can be seen from the street next to the Roman temple.
Roman gates included the Porta Principalis Sinistra (later Puerta de Gallegos) on the west side not far from the Roman mausoleum. The arches next to the Puerta de Sevilla to the east are part of a Roman aqueduct.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.