The Harhoog is a dolmen, a rectangular megalithic tomb from the Funnelbeaker culture, located near Keitum on the island of Sylt in Schleswig-Holstein, Germany. Discovered in 1925, it was moved to the present site in 1954 when a new airport was developed.
The megalithic Harhoog burial chambers were originally located near the mud-flats between Keitum and Tinnum. The stones were moved to the area near the Tipkenhoog on the coast near Keitum in 1954, when Sylt Airport was under development.
The graves at Harhoog are dated to the Neolithic and belonged to ancient settlements of the island's Funnelbeaker culture, probably around 3000 BC. There were once approximately 600 of them but today only about half of them still exist.
The megalithic tombs are built with large, rough stone slabs (one or more) which are arranged in different patterns. Harhoog dolmen is an extended dolmen, under Ernst Sprockhoff's six-category classification; the other five types are simple dolmen, great dolmen, passage grave, long barrows (without a burial chamber) and cist.
Harhhog was discovered in 1925 during excavations of earth for the construction of the Hindenburgdamm, but was only inspected archaeologically in 1936.
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.