Oranienbaum is one of the elegant satellite stops in the Dessau-Worlitz Garden Realm, built around a Baroque palace, formal gardens, and a planned town layout. It feels quieter than Worlitz, but that makes its symmetry and Dutch-influenced architecture easier to take in.
For Dessau visitors it is best treated as part of a Garden Realm circuit rather than a stand-alone city outing. Bring a bike or car if you want to link it with Worlitz, Mosigkau, and the Bauhaus sites without losing the day to transfers.