The Kalkofen estate used to be one of the most important manors in the Lower Rhine-Westphalian Imperial Circle. The complex is located in what is now the northern quarter of the city of Aachen and is surrounded by the Aachen landscape conservation area in the Wurm valley. Originally a manor, it was first mentioned in documents at the beginning of the 14th century. After various owners and renovations, it was finally converted into a pleasure palace by Johann Joseph Couven between 1750 and 1753. The Zurhelle family has owned the estate since 1831, and it has been visited by European monarchs over the course of its history. Interestingly, Napoleon's wife Joséphine even lived at the Kalkofen estate between 1800 and 1804. The complex consists of a formerly closed four-wing complex with defensive elements such as loopholes and remnants of the once closed and water-filled moat ring. Three of the original four round corner towers are still preserved. The most massive tower is located at the western corner and has two-meter-thick walls. A three-story gate tower provides access to the complex.