Ducové is famous for an archaeological site on the Kostolec hill, where an important Great Moravian castle has been unearthed. The castle, including a small palace, a Christian rotunda church, and a graveyard of local nobles, served as the administrative center of the Váh river valley during the 9th century and the first half of the 10th century. It was founded after the nearby Nitrian castle in Pobedim was destroyed during unification of Great Moravia by Mojmír I.
Ducové castle was destroyed itself by Magyar invaders around 955. Some parts of the castle (such as its palisades) have been reconstructed by archaeologists. Excavations of older settlements from the Stone Age, Bronze Age and the Roman era indicate that Ducové benefited from its location on the Amber Road well before the Great Moravian era.
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.