Château de Parthenay was built during the 13th century whose remains are still visible to this day. The castle was built on a rock by the side of the river. A citadel was built around the castle which was only accessible through the Saint Jacques gate. The gate and the city walls are still largely intact. There is another gate at the other side of the city, the Tour de l'Horloge gate. Both gates have characteristic almond-shaped towers. In total, the citadel has over 30 defensive towers, 4 entrance gates and a defensive wall with a length of over 1km.
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.