Uster Castle was built probably around 1200 by the House of Rapperswil. After the Appenzell wars Hans von Bonstetten concluded a pact with Zürich, and became a citizen of the city of Zürich respectively claimed the so-called Burgrecht in 1407. From that moment, the castle in time of war could be strengthened by a Zürich garrison. As an Austrian vassal, Zürich guaranteed a neutral status to the Bonstetten family, particularly during the Old Zürich War when the neighbouring town of Greifensee was besieged and destroyed by Old Swiss Confederacy marauders; the bodies of the defenders were buried at the Uster church.
In 1492 a fire destroyed the castle. The owners changed the following centuries many times. In 1852 the castle became the seat of the district administration, and the tower was used as a prison. In the same year the castle was rebuilt, again, and a restaurant opened. Since 1995 the castle houses the private boarding school, and the former restaurant Burg was rebuilt in a steakhouse in 2009.
From the first construction phase, the lower section of the tower, up to the level of the upper floor of the today's boarding school's building around the tower base, is preserved, but never was scientifically examined, as well as the surrounding area of the plateau. The core of the present tower measures about 11 metres.References:
The Externsteine (Extern stones) is a distinctive sandstone rock formation located in the Teutoburg Forest, near the town of Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. Archaeological excavations have yielded some Upper Paleolithic stone tools dating to about 10,700 BC from 9,600 BC.
In a popular tradition going back to an idea proposed to Hermann Hamelmann in 1564, the Externsteine are identified as a sacred site of the pagan Saxons, and the location of the Irminsul (sacral pillar-like object in German paganism) idol reportedly destroyed by Charlemagne; there is however no archaeological evidence that would confirm the site's use during the relevant period.
The stones were used as the site of a hermitage in the Middle Ages, and by at least the high medieval period were the site of a Christian chapel. The Externsteine relief is a medieval depiction of the Descent from the Cross. It remains controversial whether the site was already used for Christian worship in the 8th to early 10th centuries.
The Externsteine gained prominence when Völkisch and nationalistic scholars took an interest in the late 19th and early 20th centuries. This interest peaked under the Nazi regime, when the Externsteine became a focus of nazi propaganda. Today, they remain a popular tourist destination and also continue to attract Neo-Pagans and Neo-Nazis.