The northern curtain wall of the « town part » of the site is in places 70%, or perhaps even 80%, preserved. On the other hand, near the house just mentioned, there is a section of which almost nothing remains. This particularity can be explained by the deliberate desire of the Prince-Bishop of Liège in 1430 to demolish the fortress, undoubtedly so that it would never again constitute a threat to him or his allies in Dinant and Huy.
Today, this breach gives a glimpse of the vision that the garrison could have had towards the North, when they were on duty on the guard walk. They could easily, at a time when vegetation was less dense than at present, control any movement in the Meuse valley, towards Namur. Furthermore, it was also possible for them to monitor the outlet of the Molignée valley, a significant traffic route in the Middle Ages, and also the plateaus dominating the Meuse valley, through which one could go around and get closer to the fortress.
Nowadays, the breach mainly gives a view of the limestone cliffs of Champalle which are part of the nature reserve. This long and narrow limestone cliff facing south has become a very rare station for plants from a southern environment (e.g. Drave false-aizoon).
Several license theses (UCL) have studied calciferous vegetation (boxwood, etc.), the transformation of limestone lawn into forest: we are at the stage of the preliminary forest (birch, hazel taking over the brush) and of the irridation of southern species along the Mosan axis.
Between Champalle and Poilvache, at the foot of our viewpoint, we discover the northern valley known as « du Cimetière » (located near the railway bridge). Its vegetation is much more wooded than that of the southern valley. The land is also drier.
In the small cemetery of Houx, you can pay your respects in front of the tomb of Jean Massart, a famous and important naturalist from the ULB, passionate about the natural wealth of the Haute-Meuse.
Poilvache 