St. Germanus Church with Stadstoren (City Tower) was built in the first half of the 12th century. The church was destroyed and rebuilt several times. Parts of the original church remain from the 14th-15th century. The tower was erected in 1555. Together with plenty other belfries in Belgium and France St. Germanus Church was recognised by UNESCO as a World Cultural Heritage Site in 1999.
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.