Lichtenstein
Schloss Lichtenstein is one of those very special castles, the type that makes you think that fairy tales really do come true.  I have visited this castle many times, and am still not bored with it.  Moreover, over the years there has been a steady improvement of the grounds and today the entire area around it is very pleasant to walk.  At one time much of the outer part of the castle was overgrown.

To the left is the classic view of this castle, though there is much more to it.  Another view below shows the nature of the cliff on which the keep of this castle rests. 

Here is the official website for Schloss Lichtenstein.
Lichtenstein is just south of Reutlingen above the town of Honau, and is easy to find.  Below, some excellent "then and now" photos.  From left to right, Lichtenstein in 1946, early 1978, and 2005.  The photo on the left was taken by my grandparents. 

During World War II, American forces operating in the area thought the castle was being used by German forces as an artillery observation tower, so it took some damage to the tower, as well as some heavy machine gun damage to artifacts within.  Today, one of the mirrors still displays the impact of a .50 caliber round.  As can be seen by the right photo, extensive renovation has changed the outer appearance of the structure.
More "then and now" shots, these from early 1978 (left) and 2005.  This is the back side of the main castle, which shows how much excess vegetation has been cleared out since then.  Other minor repairs have been made as well.  For example, note the cross on the top of the wide turret to the right front.