The Schlossbergturm or Castle Hill Tower is a 35 m high observation tower on Castle Hill Schlossberg on the edge of the historic Altstadt of Freiburg im Breisgau. It has 153 steps, its top is located 463 m above sea level and thus 185 m above the average altitude of the city (278 m). The tower which was built in 2002 stands out for its unusual design consisting of twisted tree trunks (Douglas-firs from the municipal forest of Freiburg) around a staircase made of steel.