The remains of the Castle can be visited
Isenburg Castle

In the Western Ore Mountains, high above the Zwickauer Mulde valley, lies the Isenburg castle ruin. It is located between Hartenstein and the Wildbach district of Bad Schlema in Saxony.
History+
Archaeological findings suggest that Isenburg already existed in the 12th century. The name, derived from "Eisenburg" (Iron Castle), could point to regional iron mining or the supposed impregnability of the complex. Little is known about the exact circumstances of its destruction, but the castle was likely violently destroyed in the 14th century and not rebuilt thereafter.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 50.6339, 12.6739