It's said to be the oldest show cave of Germany: The Cave of Sontheim ("Sontheimer Höhle"), near Heroldstatt, within the Swabian Alps. "The oldest", because back in October 1516, Herzog Ulrich, the sovereign of Württemberg, visited the dank cave and was highly struck by its stalagmites and its huge chambers. Barely 500 years later, we did the same; stepped into the dark portal, climbed down and were mightily impressed as well.