Dilsberg Castle is a castle on a hill above the River Neckar. The castle was built by the counts of Lauffen in the 12th century. In the 13th century it became the main castle for the counts. In the 14th century it became part of the Electorate of the Palatinate and received town rights in 1347. During the Thirty Years" War, the castle was considered impregnable until Imperial forces under Tilly took the castle in 1622 after a long siege.
In 1799, French forces tried and failed to storm the castle. A 46-metre-deep well helped keep the defenders supplied during this assault. In the 19th century the castle fell into ruin and was used as a quarry. Today the castle and its town are a tourist attraction and are administered by the Staatliche Schösser und Gärten Baden-Württemberg, attracting thousands of visitors.
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.