Tour du Diable, Medieval fortified tower in Mulhouse, France

The Tour du Diable is a fortified stone tower with multiple stories and thick medieval walls constructed as part of the city's defensive system. The structure displays characteristic medieval features and was partially restored and extended in height following a fire in the early 1900s.

The tower is a remnant of the fortified wall built in the first quarter of the 13th century in Mulhouse's upper town. It was reinforced in the mid-14th century and rebuilt at the start of the 15th century. Damaged by fires in 1904, it was restored and heightened in 1906, and has been listed as a monument historique since 1929.

The tower takes its name from its use in the 15th century as a prison for people accused of witchcraft. In the 19th century the same building housed workers' lodgings, a change of use that followed the witch trials by several centuries.

The tower stands on Rue de la Tour-du-Diable in Mulhouse's upper town, where the street name marks the spot; it is a street-side vestige, not a museum with interior displays. The sources record no opening times, tickets or guided visits, so plan to view it from the street. Its base is plain stone, and the restored upper section with the pyramidal roof is best seen from a short distance.

The tower was originally part of the bishop's residence before becoming part of Mulhouse's fortifications. Its companion, the Nessel Tower, also survives from that palace but is not a protected monument, unlike the Tour du Diable, listed since 1929.