Unfortunately, the ascent/stairs to the viewing point are closed. Looks like it will be closed permanently. (As of 08/2021)
The Luisenklippe, built between 1794 and 1798, gives the impression of a steeply rising rock that can be climbed on steep steps that seem to have been carved into the rock. Attached to the rock is a single room in medieval shapes that is only accessible through a hidden door. The cliff is embedded in a cave system that ends under the Temple of Venus.
From what it looked like, the structure with rooms no longer exists today.