Carn Ban is a Neolithic chambered tomb located on the Isle of Arran. It is considered as one of the most famous of the Neolithic long cairns of south-west Scotland. It is of a type found across south-west Scotland known as a Clyde cairn. It is trapezoidal in shape, with a semicircular forecourt at the upper northeast end. The forecourt has an entrance leading into a long chamber divided into compartments by cross-slabs, similar to the arrangement at Torrylin Cairn, about 3 miles to the southwest. The chamber of Carn Ban is 30 metres long and 18 metres broad. The tomb was excavated in the late 19th century, but the only finds were a flint flake, an unburnt fragment of human bone, and a pitchstone flake.
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.