The remains of the Castle can be visited
Luttelnau Castle

The Luttelnau Castle Ruin, also known as Kattenturm, is a remnant of a medieval motte-and-bailey castle in the Ruhr Valley. Located in Essen-Kettwig, it represents the only partially preserved motte along the Ruhr, with origins dating back to the 13th century.
History+
In the 13th century, the residential tower of Luttelnau Castle was built on an island in the Ruhr and later transformed into a motte. In the 14th century, the complex was a fief of Werden Abbey, owned by the Lords of Luttelnau, documented since 1296. Contrary to older assumptions that the castle was destroyed after the Battle of Worringen in 1288, excavations from 1968 confirm construction activities in the 14th and 15th centuries. Traces of fire could indicate a destroyed wooden palisade or a bridge to the outer bailey, possibly during a plundering in 1317. During this period, additions were also made to the tower. After the extinction of the Lords of Luttelnau in 1417, the castle passed as a fief to Heinrich von Oefte in 1424 and subsequently fell into disrepair. By 1454, it was already described as “desolate,” and by the end of the 16th century, it still served as a prison. Since 1985, the ruin has been protected as a historical monument and was additionally designated an archaeological monument in 1992.
Image: http://www.wehrbauten.de/thread.php?threadid=575
Location: 51.3687, 6.9612