Rheinfels            

The massive nature of the structure can be seen in these photos.  At left, one of the entrances into the fortress wall.  Below, views of the walls on the west side.

A view toward the curtain wall from one of the inner walls (left).  At one time Rheinfels had a garrison of over 4,000 men.  And these were largely paid and supported by family money by the owner of the fort.  Below, the back side of the fort.  This area was actually still part of the castle structure.  The larger fortification from the 1600s which was to the west is no longer extant.

To provide one with an idea how huge this fortress was, on the left is a color-adjusted photo of the model of Rheinfels based on the 1607 plans.  The view is from the river side looking west.  All that remains now is the forward castle area.  The fortifications beyond are gone.

Below, a view to the main tower from the back area of the castle.  There were once a number of structures here to house troops and support personnel.  Today it is a pleasant park for children to play in.

A diagram, left, illustrating the complexity of the remains of this once huge and awesome fortification.  The diagram is rotated to match the model above.  Here is the Rheinfels official website.