Burg Ringelstein, Medieval castle ruins near Büren, Germany

Burg Ringelstein is a castle ruin on a ridge above the Alme Valley near Buren. The site contains underground passages, stone-vaulted cellars, and a defensive tower standing about 20 meters tall.

The Davensberger noble family received permission from the Archbishop of Cologne in 1383 to build this fortress. During the Thirty Years' War the stronghold lost importance and gradually fell into ruin.

The name Ringelstein first appears in writing in 1399, when Berthold von Büren redeemed the castle from pledge. A 1574 inventory lists twelve rooms, a kitchen, egg, wine and meat cellars, a brewhouse, a bakehouse, a stable and a grain loft. The Hexenkeller, a cellar tied to the witch trials, can still be seen in the ruin.

The ruin sits on a hilltop requiring a short climb to reach. Excavations since 2005 have uncovered structures from different building periods, though parts remain under restoration work.

The castle's surviving cellar, known as the Hexenkeller, held the court and torture chambers of the Büren lordship. In 1631 alone, 55 people were condemned and executed as witches within 30 days, a episode documented by finds in the cellar.