Wallburg Bruchhauser Steine, Hilltop fortification in Olsberg, Germany

Wallburg Bruchhauser Steine is a hillfort on the 728-metre Istenberg near Bruchhausen in Olsberg, enclosing the four rocks Feldstein, Goldstein, Bornstein and Ravenstein. A collapsed cyclopean wall runs from the Feldstein to the Goldstein, with a moat in front; another wall between Goldstein and Bornstein blocks access from the northeast, and a dry-stone wall on their west side encloses a square of about 0.6 hectares.

The hillfort on the 728 m Istenberg dates to the Late Hallstatt period, around the 5th to 6th century BC, with activity also in the 3rd century BC. It protected nearby iron and copper mining; a use as a cult site is possible but unproven. In the early Middle Ages the site was used and expanded again.

The site's name refers to the broken rocks and valley, marking where people lived and worked across many centuries. The rock formations still shape the local landscape today, showing how settlements and the natural environment were closely connected.

Access is via marked hiking trails starting from an information center that houses exhibits on geological and historical features. The routes are well-signposted, and the climb requires moderate physical fitness.

The four rock masses have individual names - Goldstein, Bornstein, Feldstein, and Ravenstein - with cyclopean walls carved directly into the stone formations. This building method shows how builders used the natural landscape as the foundation for their structures.