Burg Wartenberg, Castle ruin on the Wartenberg in Geisingen, Germany

Burg Wartenberg is a ruined hilltop castle on the 810-metre Wartenberg, the northernmost Hegau volcano, two kilometres west of Geisingen. Its core is a 13-by-22-metre residential tower built in 1140 from basalt blocks, with walls over three metres thick, surrounded by an enclosing wall still five metres high. The photograph shows a broad, uneven face of irregular grey and whitish stones laid in courses, heavily coated with bright green moss, with protruding blocks and recessed pockets and thin bare branches against the stonework.

Construction began around 1140 when local rulers built this fortress as both a military post and a residence. Over several centuries it remained important to the region before eventually being abandoned and falling into ruin.

The ruins shape how locals and visitors understand medieval life in this part of Germany, showing how power was organized in the countryside. Walking through the site, one can sense how this fortress once controlled the surrounding lands and communities.

The ruins are accessible year-round through marked hiking paths with no barriers to entry. Informational signs on-site explain the main features and how the castle developed over time.

The Wartenberg is the northernmost volcano of the Hegau, and the castle takes its name from this 810-metre wooded summit. The lords of Geisingen, first recorded as "Cono miles de Gisingen" on 2 February 1095, later called themselves von Wartenberg after the site. Their standing lion still appears in the arms of Geisingen, Öfingen and Fürstenberg.