Carreg Samson is a 5000-year-old Neolithic dolmen located half a mile west of Abercastle. It has a capstone, 4.7 metres by 2.7 metres and 1.0 metre thick. The capstone rests on three of six stones 1.1 to 2.2 metres high.
The whole burial chamber was once covered by a mound of earth or stones and once these were removed stones were used to block the holes in the sides of the tomb so that it could be used as a shelter for sheep.
The site was excavated in 1968 which revealed four additional stone-holes, one having supported a further chamber stone, the others indicating a possible passage leading off to the northwest. Slight traces of a covering cairn were found to the south and it was shown that the monument had been raised over a pit 0.8 metres deep, filled with clay and stones. Finds included a small quantity of burnt bone, pottery, and flints.
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.