Kong Asgers Høj (King Asgers Mound) is a large passage grave on the island of Møn. It was built in the Late Stone Age (3000 BC - 1500 BC) and has a 10 meters long narrow passage leading into to the grave chamber. The grave chamber is 10 meters long and 2 meters wide and was when in use a common grave. When somebody died the grave was opened, the deceased was buried, and the grave was closed again. Kong Asgers Høj is situated to the Northwest of Sprove on a small hill. The passage grave is open to the public, but it is a good thing to bring some sort of light because the grave chamber is pitch-dark.
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.