The Abbey of Saint-Roman is a cave monastery which includes the ruins of a castle (château de Saint-Roman-d'Aiguille), a chapel, cloisters, terrace, tombs and walls. It was constructed in the 9th, 10th, 12th and 15th centuries.
The abbey is reached by a signposted path from Beaucaire which leads past a vast chamber and the monks’ cells to the chapel carved out of the rock which contains the tomb of St Roman. From the terrace, there is a fine view over the Rhône, Avignon and the Mont Ventoux area with Tarascon in the foreground.
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.