Montclair
There is not much left of the authentic Monclair.  The original twin round towers are mostly gone, and only portions of the walls and flanking towers remain.  Nevertheless, it is still a good castle to visit, though to reach it you need to take a good half hour hike (below). 

Left, one portion of the castle linked by a modern walkway.  This would be where the main gate took you into the inner ward.

These photos were taken in  2008.
Montclair has a long history, having originally been a Roman fort (c25 AD) to becoming a Celtic hillfort (c300-500 AD).  A few hundred years later a wooden castle called Skiva was built by expanding a fortified farm.  This castle was destroyed by Poppo, the Archbishop of Trier in 1016.  The site was so important that another castle was started closer to the bend in the Saar River.  This "Monkler" castle was started in the 1160s, the name shown on official documents in 1190.  The family of Arnulf von Walecourt who received the site from the Archbishop of Trier determined to take this new castle and make it the most important and impregnable in the region.  Nevertheless, this structure was destroyed in 1351. 

A new castle, composed of the current remains visible today, was started in 1439 under the Clermont family.  In 1442, the castle was then handed to the Sierck family, who finished the castle and held it until the family intermarried with the powerful von Sayn family.  When the last member of the Sayn family died out in 1583, the castle was passed to another family.  In 1606, the site reverted back to the Archbishop of Trier, but appears to have been largely abandoned as too expensive to maintain.  All told, six families owned the new site throughout its history, and the castle became the basis of many myths and legends.
Above left, a model of the original castle.  Above, a view from within the area where the main towers once stood.  The castle design was quite unique in that it had a keep that was composed of two towers that covered the gate into the inner ward, and had two flanking towers (right) to cover the back.

Left, one of the restored interior sections to give an idea of how the fortress was constructed.  It is uncertain to me if the central pillar was a recently restored original or a completely recent addition.
Right, another view of the small inner tower that was placed between the two round towers at the gate.

Below, one of the stairways that take you into the few lower chambers that still exist.  The steps appear to be authentic showing the wear and tear of many years of foot passage.
Right, the interior wall of one of the round towers.  The various levels, of which there were four, would include full living quarters.



Below, the same stairs as seen above, but now seen from the top looking down.
Above, a recent addition of stairs to one of the stair towers to take you to the top of the round towers. 


Left, a good view of the interior of the round towers which were quite massive.  The nature of the site indicates extensive restoration work to smoothe off the jagged edges of the walls.