Alte Burg, Medieval castle ruin in Osterode am Harz, Germany

Alte Burg is a ruined spur castle on a 40 by 60 metre site on the Butterberg slope above Osterode am Harz. Only the eastern half of its round bergfried survives, standing 34.5 metres high; the western half was removed in 1654, probably for building stone. The tower originally had a diameter of 15 metres, walls up to 3.5 metres thick and six storeys, with a spiral staircase inside the wall.

The fortress first appeared in written records in 1153 under the control of Henry the Lion. It later became the seat of the dukes of Grubenhagen before falling into ruin after the early 16th century.

The ruins sit within a cemetery today, showing how medieval fortresses were woven into local life and landscape. The tower remains a landmark that reflects the power local nobles once held over the region.

The ruin sits on cemetery grounds and remains visible from outside, with the tower being the most striking element to see. Visitors should remember this is an active cemetery and treat the area with appropriate respect.

The bergfried's west half was demolished as early as 1654, likely quarried for stone, leaving only the eastern half standing at its full 34.5 metres. Inside the surviving wall, a spiral staircase still winds upward. The round tower originally had six storeys, not five.