The remains of the Castle can be visited
Falkenstein Castle

The Falkenstein Castle Ruin, also known as Neu-Falkenstein, is a hilltop castle in the Taunus region. It stands above the eponymous district of Königstein.
History+
Falkenstein Castle was built in the mid-14th century by the Lords of Bolanden-Falkenstein, directly adjacent to the older Nürings Castle. It was first documented in 1364 in connection with the Imperial War against Philipp VI of Falkenstein. The castle rapidly changed owners, including the Counts of Sponheim, Philipp of Nassau, and the Lords of Hattstein and Kronberg. Around 1500, the complex underwent expansions, including the reinforcement of the curtain wall with flanking towers and the construction of a late Gothic keep.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Joachim Schneeleopard
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 50.1903, 8.4767