Rodenberg Castle and Local History Museum

Not much remains of the castle, but there is a lovely local history museum in the building.

museumslandschaft-rodenberg.de/freilichtmuseum

[...]
Under the honorary direction of Erich K. Schales, a mighty hexagonal bastion from the beginning of the 16th century, together with the weir attached to it, was excavated and partially walled up. A protruding roof resting on external steel supports, a protective roof over the weir, as well as grids and fences protect the facility in the long term. At the same time, a round tower (Rondell) built around 1480, as well as an interlocking weir, was excavated and a roof was provided after the masonry had been renovated.
[...]

The castle is a must-see when crossing Rodenberg. At the ditch around it you will find many ducks (feeding forbidden) and behind that is a park with a playground.