Machrie Moor Stone Circles is the collective name for six stone circles on the Isle of Arran. Six stone circles are visible on the moor immediately east of the derelict Moss Farm. Some circles are formed of granite boulders, while others are built of tall red sandstone pillars. The moor is covered with other prehistoric remains, including standing stones, burial cairns and cists. Several hut circles can also be seen as low rings of turf-covered stone.
The six stone circles are situated below a prominent notch on the skyline to the northeast where Machrie Glen divides into two steep-sided valleys. At the summer solstice the notch is intersected by the sun at sunrise, and this may explain why the circles were sited in this location.
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.