Narrenmühle, Post mill in Viersen, Germany

The Narrenmühle is a post mill with wooden construction and large rotating blades designed for grain milling. The structure displays the craftsmanship typical of such mills built in this region.

The Narrenmühle was built in 1809 as a privately financed grain mill by Holtz, the former tenant of the Tränk(en)mühle; an inscription on the drive wheel of the former milling gear attests to this. Unlike the 1506 Tränk(en)mühle and the 1556 Hochmühle, it was not a cameral mill subject to milling obligation. The city acquired it in 1906, raised it by 1.80 metres in 1912 and set up a museum; in 1950 it passed to the Dülken Fools' Academy.

The name refers to the Dülkener Narrenakademie, the "Riding Academy of Arts and Sciences", which has occupied the mill since 1950. Every 11 November its members ride wooden hobby horses around the mill to open the Dülken carnival session, a custom traced back to the 18th century. Old medals, flags, hats and books documenting it are kept in the mill museum.

The mill stands on Rheindahlener Straße on the left bank of the Lower Rhine in the Dülken district. Since April 2020 it has been dismantled and moved to a specialist workshop in Afferden, the Netherlands, so the building itself cannot be visited at present. The lower part housed the fools' museum and the upper "Weisheitssaal" hosted the academy's sessions.

The mill's brick-walled trestle is a rarity in post-mill construction, resembling the tower-cottages (torenkotmoelen) otherwise found only in Flanders. Since 1950 the building has belonged to the Dülken Fools' Academy, which holds its sessions in the upper "Hall of Wisdom" and keeps a fools' museum below.