Himlštejn Castle, Medieval castle ruin in Peklo, Czech Republic

Himlštejn Castle is a ruin on the 638-metre summit of Nebesa in the Doupov Mountains, about one kilometre north-west of Stráž nad Ohří. The remains include the portals of two gates, the lower walls of a residential tower, and fragments of palaces and fortifications.

Vilém z Ilburka had the castle built before 1434 and named it Himmelstein, German for "Heaven's Rock", as a counterpoint to the neighbouring village of Peklo ("Hell"). After Vilém moved to Hauenštejn, only a burgrave resided here. The Šlik family acquired it in 1528 and let it decay; by 1547 it was recorded as deserted.

The castle ruins maintain their status as a registered cultural monument in the Czech Monument Catalogue under number 1000133658, preserving medieval architectural heritage.

The ruins are accessible by foot via a hiking trail that passes through rock passages and crosses wooden footbridges through the Peklo valley. The terrain is rocky and uneven, so sturdy footwear and careful footing are important for a safe visit.

The castle's name, Himmelstein (Sky Rock), was chosen by Vilém z Ilburka as a deliberate contrast to the neighbouring settlement of Peklo (Hell). The two names sit about a kilometre apart on the slopes of the Doupov Mountains.