Carn Euny is an archaeological site near Sancreed, on the Penwith peninsula in Cornwall with considerable evidence of both Iron Age and post-Iron Age settlement. Excavations on this site have shown that there was activity at Carn Euny as early as the Neolithic period. There is evidence that shows that the first timber huts there were built about 200 BC, but by the 1st century BC, these had been replaced by stone huts. The remains of these stone huts are still visible today.
Carn Euny is best known for the well-preserved state of the large fogou, an underground passageway, which is more than 20 metres long. This fogou runs just below the surface of the ground and is roofed with massive stone slabs.
The site was abandoned late in the Roman period.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.