King Arthur's Hall is a megalithic enclosure on Bodmin Moor in Cornwall, England. It is thought to be a late Neolithic or early Bronze Age ceremonial site.
The monument consists of fifty-six stones arranged in a rectangle with a bank of earth around them and measures approximately 20m by 47m. The interior fills with water and a contemporary ground level has not been established. It has suffered damage by cattle in the past and is now protected by a gated fence. It can be reached by footpaths east of St Breward.
The surrounding area contains many stone circles, hut circles, cairns and cists.
In the absence of any archaeological finds, its origin and use is only speculative. A similar enclosure exists in Brittany which was a Bronze Age cremation site, but a similar rampart construction at Lough Gur in Ireland suggests an earlier Neolithic date. It has even been suggested that it was merely a medieval cattle pound, but the effort required to build the bank and to erect the slabs suggests that it had a more important function.
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.