Hohentwiel

Infobox Mountain
Name=Hohentwiel
Photo= Hohentwiel-luftbild.jpg
Caption= Aerial photo of the Hohentwiel
Elevation=convert|686|m|ft|0
Range =
Location=Baden-Württemberg, Germany
Prominence =
Coordinates = coord|47|45|53|N|8|49|08|E|region:DE-BW_type:mountain|display=inline,title
Topographic

Type=|Age=
First ascent=
Easiest route=
Pronunciation=The Hohentwiel is an extinct volcano in the Hegau region of Baden-Württemberg in southern Germany. About 20 miles (30k) from Lake Constance, it lies in the German city of Singen

The Hohentwiel was begun, along with the chain of volcanoes in the Hegau, about 7-8 million years ago, when a layer of volcanic ash and stone was laid down. The magma consists of Phonolite. In the following millions years the core was opened by the glaciers from the ice age 260 metres beneath the surface. This formed the core that is now exposed, after the ensuing millions of years of erosion.

The fortress whose ruins top the Hohentwiel was begun in 914 with stone taken from the mountain itself by Burchard III, Duke of Swabia. Originally, the monastery of St. Georg was contained within the fortress, but in 1005 it was moved to Stein am Rhein (now in Switzerland}, and the Swabian dukes lost control of the Hohentwiel.In the later Middle Ages the noble families von Singen-Twiel (12.-13 cent.), von Klingen (to 1300) and von Klingenberg (to 1521) resided here. In 1521, it passed to Duke Ulrich von Württemberg, who developed the Hohentwiel into one of the strongest fortresses of his duchy.The fortress resisted five imperial sieges in the Thirty Years' War.The Hohentwiel served in the 18-th century as a Württemberg prison.The fortress was destroyed in 1800 after peaceful handing over by the French.Today the former fortress Hohentwiel is one of the biggest castle ruins of Germany.

The modern city of Singen (Hohentwiel) nestles at the foot of the mountain.

ee also

*List of volcanoes in Germany

External links

* [http://www.p-stein.de/hohentwiel-rundgang71.htm virtually Hohentwiel tour]