Between the 15th and 18th centuries, Bentheim sandstone was a small industrial empire. Quarried from outcrops at Gildehaus and the main town, it was shipped to Munsterland, East Frisia, the Netherlands, Belgium, and Denmark. The Royal Palace in Amsterdam is made of it. The theater and the Church of Our Lady in Antwerp. The Catholic Church in Aarhus. The tower of the Martini Church in Groningen, completed in 1482. The City Hall in Munster. There is even a long-standing local claim that the pedestal of the Statue of Liberty in New York is Bentheim sandstone - though Obernkirchen claims that one too, and the matter is unresolved. What is certain is that, for three centuries, fortunes elsewhere were built on rock cut from this hillside.

Burg Bentheim first appears in a 1116 document as a stronghold of the Counts of Bentheim, and unlike most medieval castles in this part of Europe, it never became a ruin. It is still owned by the Princes of Bentheim-Steinfurt, still partly inhabited, and partly open as a museum. The high keep, called the Pulverturm or Powder Tower, gives visitors a view across the rolling green Grafschaft Bentheim and, on clear days, far into the Netherlands. The Dutch landscape painter Jacob van Ruisdael painted it in 1653, recognizing what locals already knew: a castle on a wooded crag in flat country is a gift to anyone with a paintbrush.

Around 1711, someone discovered curative sulphur springs bubbling up beneath the town. By the 19th century, Bentheim had become a respectable spa - Bad simply means bath. Queen Emma of the Netherlands brought her fifteen-year-old daughter Wilhelmina here in 1895 for several weeks. Otto von Bismarck took the waters before that, as did Kaiser Wilhelm I. There is still a sandstone Bismarck on the Bismarckplatz, looking faintly imperious in the shadow of the castle. Only in 1979 did the town officially become Bad Bentheim - the Bad acknowledging more than two and a half centuries of brine and sulphur cures.

Centuries of stone-cutting left holes in the hillside, and the town turned several of them to good use. The Bentheimer Freilichtbuhne, an open-air stage, sits inside three disused quarries - a natural amphitheater with sandstone walls that catch and warm the evening light. Plays run all summer. Beside it is the Franzosenschlucht, the Frenchman's Gorge, named after Napoleon's troops who passed through here. The Bad Bentheim Sandstone Museum, housed in a 17th-century Ackerburger house, walks visitors through the geology and trade of Bentheimer Gold. On Monday, Friday, and Saturday evenings at 9 o'clock, a Night Watchman in costume leads free walking tours that begin at the lower castle gate, mixing legend with documented history.

Bad Bentheim sits on the Dutch border - close enough that Almelo, Hengelo, and Enschede are easier to reach than most of Lower Saxony. In 1945, the Bakker-Schut plan would have annexed this whole strip of Germany into the Netherlands as reparations; American objections killed the proposal. Today the border barely registers. Buses run from town to Gronau, just over in North Rhine-Westphalia. The IC-77 from Amsterdam to Berlin always stops at Bad Bentheim station - not for passengers, but because Dutch and German trains use incompatible electrical systems and the locomotive has to be changed. It is one of the more honest border ceremonies left in modern Europe.