Burgruine Ried

The Ried castle ruin is the ruin of a spur castle on the local mountain of Ried am Riederberg in the Vienna Woods, which, according to the current state of research, was probably built around 1200. Today only sparse remains of a Romanesque round tower ruin, a kennel wall and the outer castle are preserved.
The remains of the castle complex are located on a 320 m high hilltop in front of the Klosterberg to the northwest, with the field name Hausberg around 1 km south of Ried am Riederberg. The approximately 3000 m² large, Hausberg-like core castle is surrounded by a moat and an impressive system of ramparts and ditches.
Source and more information: de.wikipedia.org/wiki/Burgruine_Ried

Short nice hike near Vienna. Also suitable for small children.