Madenburg
A view of both the outer (left) and inner (right) ringwalls. This section is on the north side near the main entrance.

Madenburg's walls vary from as little as 2 meters to as much as 5 meters thick.

The castle has a trail that takes you completely around the outside of the inner ringwall. However, this trail does get quite challenging (see photo below), with the area lined with stinging nettles.

Left, I just snapped this shot when a sentry German Shepherd decided to intevene. I had heard the barking, but falsely assumed that the dogs were restrained or in a kennel. Not so. This beast stood above me about 8-10 feet, leaning over the edge and ready to pounce. This is the western side of the castle.
Left, this photo shows a portion of one of the northern shield walls.

Below, another view of the western side of the castle. I'm sure Madenburg would be nice to see from within... but alas, it was not to be.
Below, a beautiful panoramic of the valley below Madenburg, the terrain stretching out towards the Rhein River.