Grebenstein Castle, Medieval castle ruins in Grebenstein, Germany.

Grebenstein Castle is the ruin of a medieval fortified structure sitting on a distinctive basalt cone. The remaining outer walls and residential building still display the original construction method, with defensive elements integrated throughout the entire complex.

A first castle stood here in the second half of the 11th century. From 1266 Count Ludolf V. of Dassel enlarged it, and it was first documented in 1272; in 1297 Otto of Everstein sold castle and town to Landgrave Henry I of Hesse. Troops of Archbishop Adolf I of Mainz besieged it in vain in 1385. Swedish troops destroyed castle and town in 1631 during the Thirty Years' War, after which residents quarried the ruin for rebuilding stone.

The castle served as a symbol of local authority and continues to shape the town's character today. Its elevated location made it a recognizable landmark for people throughout the surrounding region.

The ruins can be reached via several paths from the town, with stairs leading to the upper level. The climb takes some effort, but you get a wide view of the landscape from the top.

The castle hill is a basalt cone around which the Esse river flows, and the ruins include a 37-metre-long hall whose outer walls still stand over 13 metres high. A steel staircase now leads to a viewing platform on the upper masonry.