The neo-Gothic Schloss Drachenburg looks medieval but was actually built in the 1880s. It houses exhibits on the building's history, the ongoing restoration process and the history of nature protection. Perhaps more interesting, though, are the lovely grounds with their terraces, fountains and tower, which can be climbed for expansive views.
Combination tickets with the Drachenfelsbahn nostalgic train ride cost €15/9 adult/child (KönigswinterKombiKarte K3).