The first textile factory opened in Gronau in 1854, and the population followed the spindles. Dutch investors put up much of the capital - this was an industrial town that thought of itself as half a Twente town, and traded that way. By 1875 railway lines ran from Gronau to Munster, Dortmund, and Enschede. By the First World War the town had a new town hall, a district court, schools, hospitals, an indoor swimming pool, waterworks, an electricity plant, and a city park - all of it paid for by cotton. And then, in 1980-1981, M. van Delden & Co. - the firm that had started it all in 1854 - went bankrupt. The textile era simply ended.

On the night of 9 to 10 November 1938, the synagogue on Wallstrasse was desecrated as part of the coordinated nationwide pogrom the Nazis called Reichskristallnacht. Most of the Jewish residents of Gronau and the neighboring district of Epe were eventually deported to extermination camps and murdered. A Jewish cemetery survives in Gronau today as a place of remembrance. In Epe, the former synagogue is being rebuilt as a cultural center - an attempt, decades late, to remember what was destroyed and the people who were taken.

Udo Lindenberg was born in Gronau in 1946 - a year of food rations, occupation zones, and stunned silence about what had just happened. He grew up in a town where the German rock and pop scene barely existed yet, where rock music was something that came from somewhere else and was sung in English. Lindenberg changed that. Starting in the 1970s, he insisted on singing rock in German - and not the polished German of the Schlager hits, but slangy, sardonic, streetwise German. He became one of the defining voices of German popular music and a one-man argument that you could be both rock and Deutsch. Today Gronau honors that heritage with a rock and pop museum that has become one of the town's main draws.

When the mills closed, the town needed reasons to exist beyond cotton. The Jazzfest Gronau, launched in 1989, has become one of them. The program reads like a serious jazz festival in any major capital: Jan Garbarek, McCoy Tyner, Klaus Doldinger's Passport, Al Di Meola, Avishai Cohen, Al Jarreau, Maceo Parker, Gregory Porter, Ron Carter. Annual attendance runs between 12,000 and 18,000 including open-air events, and roughly two-thirds of those visitors come from outside Germany - many of them driving over from the Netherlands, just as their grandparents drove over to buy and sell cotton.

In 1912 someone digging in Gronau pulled up the skeleton of a Cretaceous plesiosaur - a long-necked marine reptile that swam here when this whole corner of Europe was warm shallow sea. The fossil now lives in the Geological-Paleontological Museum in Munster, where it has been studied as Gronausaurus wegneri, named in part for the town that produced it. The plesiosaur and the textile mill are roughly the two poles of Gronau's identity: a stretch of fenland flat enough that the sea once covered it, and industrious enough that, for 130 years, looms covered it instead.