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:Bomarsund fortress and garrison was built in 1832-1854 by Russian Empire to defence Åland Islands against enemies. British and French fleet attacked against it during the Crimean War in 1854. After a week of fighting the British stormed the remaining fort. Anglo-French forces destroyed it totally after battle. In the Treaty of Paris 1856, the entire Åland Islands were demilitarized, which is a status that has been preserved until this day.
Nowadays there are some ruins left and fortress area is open for visitors.