Metternich
The climb to the castle is easy and well-marked.  The entrance demonstrates how extensive the structure was at one time.  Since its destruction in 1689, it has not been rebuilt, but only slightly repaired.  Therefore, a visit to this castle offers the explorer the chance to see a real medieval structure.
As you enter the castle proper you will begin to see some of the outer walls that protect the inner ward.  Within virtually all of the interior structures have been destroyed, but you can trace the wall foundations  and remnants to get an idea of what rooms housed what.
To the right is view of one of the outer walls showing at least three stories to part of the inner structure.  The floors were obviously wooden support beams overlaid with wooden planks.  Hence they were burned when the castle was destroyed in 1689.  The turret to the right was positioned to not only protect the entrance area to the main building, but also the main gate as well.
Left, the same stretch of wall as above, this time from inside.  The piled up soil in the lower right has filled in what was once the lower floor.  The two rows of windows represent the second and third stories.  An interesting aspect of the wall is that there is no structural indent at the base of each set of windows as to where to rest the floor joists.  Moreover, there is little evidence of large slots for the joists, though a close examination of the photo revealed slight indents that could serve as such.  As this is the case, then it is obvious that Metternich's floors were probably very large, with heavy vertical support beams liberally installed on each level, since these would need to bear the weight of the static and dynamic loads on each floor. 

This wall does show some evidence of cement paste applied to retard the decay of the structure.
Right, another view of this same wall, this time from above.  Note the fireplace, with the chimney rising above it.  This room served as the residence for the fortress commander.  A wall once extended from the right of the chimney nearly perpendicular from the wall still standing.

Below, an arched entrance way into the inner ward.  Note the uneven character of the brickwork as a good portion of the mortar has eroded away.  Much of the brickwork was rough and unrefined.