This is a long hike that takes you to some of the more impressive-looking medieval structures in the Maas Valley. Whereas most of the castles in the region are either Renaissance or Baroque palaces, the castles here will at least appear more medieval.
Hiking: Lesse Heights
Unlike most of the hikes on this site, this one is just for the natural beauty of the Ardenne. Since much of the forest is less "forest" and more "curated agricultural land", its nice to find a spot where the forest seems dense and ancient.
Hiking: Castles of the Maas
The highlights of this trip will certainly be the Warfusee and Jehay Palaces, both of which are museums and both have regular opening hours. At certain points along the river you will also get sweeping views of the River, though not as impressive as elsewhere.