Geismühle, Historical windmill in Krefeld, Germany.

Geismühle is a tower windmill in Krefeld with a cylindrical brick body and rotating sails that capture wind to power the grinding mechanism inside. The structure features a typically German mill design where the entire upper section rotates to face changing wind directions.

The Geismühle is around 700 years old, making it one of the oldest surviving windmills on the Lower Rhine. It was probably built not only as a mill but also as a watchtower guarding the Hohe Weg, a medieval trade road, for the stewards of the Count of Cleves. Until 1575 Heerdt and Büderich also belonged to its compulsory milling district. Hessian mercenaries besieged and plundered it twice in the Thirty Years' War; around 1800 it passed into private hands, and in 1945 a bomb badly damaged it.

This windmill reflects the agricultural roots of the region, serving as a place where farmers once brought grain to be processed into flour. It stands as a reminder of how communities depended on such structures for their daily bread.

The mill stands on the west side of the A57 motorway rest area of the same name, just outside Bösinghoven, and is reached on foot or by bike. The interior opens on the first Sunday of each month from May to October, 14 to 17; the grinding mechanism turns when the wind allows. A hill was piled around the base for the turning gear, so the former ground floor became a grain cellar.

The mill's windows are shaped as arrow slits and two chimneys survive inside, unusual for a mill because of fire risk: it was likely built as a watchtower guarding the Hohe Weg trade road for Burg Linn, 2.5 km away. Hessian mercenaries besieged and plundered it twice in the Thirty Years' War.