Get to Singen with regional trains (Interregio) via Offenburg, Stuttgart or Ulm. Here take the SBB-train to Singen Landesgartenschau. From here walk approx. 20 minutes (follow the signposts).
Use the freeway A81 (Würzburg - Stuttgart - Singen) and use the "Singen" exit. Go ahead in "Mühlhausen-Ehingen" direction and later to Singen. Follow the signposts to "Hohentwiel" here.
From the Friedrichshafen airport take the IRE to Singen and here take the SBB-train to Singen Landesgartenschau. From here walk approx. 20 minutes (follow the signposts) ore take a cab.
Variable opening hours (see website)
The fortress, whose ruins lie on top of Hohentwiel, was built in 914 using stone taken from the mountain itself which is an extincted volcano. It's the largest castle ruin in Germany.
After having resisted five sieges during the Thirty Years War the former castle was used as a prison till its destruction in the year 1801 by troops of the french emperor Napoleon Bonaparte. The elevation of the volcano Hohentwiel is nearly 700 meters, and being up there one has an astonishing view over Lake Constance, the Thurgau and the Alps (as soon as the weather is clear enough).
Today the imposing fortress ruins Hohentwiel (Festungsruine Hohentwiel) are a paradise for the visitors, especially for kids. There are thousands of locations to play hide-and-seek.
The foot path up to the peak is partially very steep and exhausting. But once you arrive at the top, you will be compensated for any effort. Enjoy the stunning view, let the history of the fortress simply play itself out and absorb the unique atmosphere of the area.
As for the opening times see http://www.festungsruine-hohentwiel.de/en/visitor-information/
More than 40 years ago the Hohentwiel Festival was established, one of the oldest open air festivals in southern Germany. In the beginning it was a little city festival with live music, later it used to be a Jazz festival with international stars like Miles Davis or Dizzie Gillespie. Nowadays it's one of the largest music events in the entire area. Stars like B. B. King, Chris De Burgh, Joe Cocker or Patricia Kaas already played here. But the festival doesn't just have the music - the unique atmosphere of the location itself is what makes this festival something very special. Once each year a large number of visitors come to Singen.
Escape Address: Auf dem Hohentwiel 2a, 78224 Singen, Singen, Baden-Württemberg, Germany
The Rhine Falls - located near Schaffhausen (Switzerland) is Europe's largest plain waterfall. They are 150 m wide and 23 m high. The Rhine Falls arised during the last ice age, approx. 14,000 to 17,000 years ago. There are boat trips available to view the falls directly from the front. Furthermore there are viewing platforms.
The grape varieties Müller-Thurgau, Bacchus, Pinot Gris, Pinot Blanc, Riesling, Traminer, Kerner, Chardonnay, Pinot Noir, Fornfelder and Cabernet Sauvignon are grown on approximately 22 hectares around the Hohentwiel. Germany's highest vineyard can be found here: 530 m above sea level. There are several wineries who are offering wine tasting.
Visit the Wildlife and leisure park Allensbach. Allensbach is located directly at Lake Constance, not far away from Singen. More than 300 wild animals - deer, boars, bears, lynx and more can be viewed here. Playgrounds, petting zoo, giant slides, climbing camp, and many more attractions for both kids and adults are available as well.