The Mên-an-Tol is a small formation of standing stones in Cornwall. It consists of three upright granite stones: a round stone with its middle holed out with two standing stones to each side, in front of and behind the hole. When seen at an angle from one side, the stones form a three-dimensional '101'.
The site probably dates from the late Neolithic-early Bronze Age (approx. 2500-1500 BC) as do the other stone circles in West Penwith, and was probably used for ritual and ceremonial purposes.
The two side stones are both about 1.2 metres high. The westernmost stone was moved and brought into a straight line with the other two stones sometime after 1815. The holed stone is roughly octagonal in outline. It is 1.3 metres wide and 1.1 metres high; the circular hole is 0.5 m in diameter. The only other holed stone in Cornwall of this type is the Tolvan holed stone which can be seen in a garden near Helston.
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.