Franchimont Castle sits at the western end of a small hill overlooking the village of Franchimont. It is thought to have originally been built in the 11th century, as a stronghold of the Principality of Liège. The original building was extended several times during the Middle Ages, once after a fire in 1387.
In 1487 the castle was besieged, and around the same period the La Marck family took ownership of it. In the early 16th century the outer wall was built, with casemates and an artillery tower added.
Today the castle is owned by the town of Theux and is open to the public. The artillery tower at the north-east corner contains a small exhibition and the ticket office.
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.