Reussenstein
and Ruine Limburg
From the walls of Reussenstein one can see for miles over the surrounding countryside.  Its position along a rocky crag is the main element of its defense.

However, before this castle was built, this location as well as several others in the area were the sites of ancient Celtic hill forts.  Visible from Reussenstein is the ruin of Limburg, which clearly shows signs of being a hill fort.
Below left and below, two views of the Limburg ruin.  The sculpted slopes are the foundations for wooden palisades that were erected close to 1,500 or more years ago.  Later, a small castle was built on the top of this site, but the foundations of the wooden walls are still visible today.