The ruined castle Burg Drachenfels, on the summit of the Dhill, was built between 1138 and 1167 by Archbishop Arnold I of Cologne and bears the same name. It was originally intended for the protection of the Cologne region from any assault from the south. Originally it consisted of a bergfried with court, chapel and living quarters for servants. The castle was slighted in 1634, during the Thirty Years' War, by the Protestant Swedes and never rebuilt. As a strategic asset it had outlived its usefulness. Erosion due to the continued quarrying undermined much of the remains and only a small part is left today.
References:The first written record of church in Danmark locality date back to the year 1291. Close to the church are several stones with a Christian text and cross inscribed. The oldest parts of the present red-brick church are from the 1300s. In the late 1400s the church was enlarged to the appearance it has today. The church has been modified both internally and externally several times, among other things after the fires in 1699 and 1889. There are lot of well-preserved mural paintings in the walls.