The Chateau Fort (fortress)
This fortress is the biggest one in Europe and was build around 1424 and extended during the next centuries. Having 35000 square meter, it looks impressive with its four bastions. Unfortunately only a part of this fortress can be visited, and the court rather looked like a building site (although I would say that the fortress is well preserved - too well, I more like ruins!).
If you read something about "Historium" - that's the visit of the castle. Several scenes of the life there are reconstructed, for example some guards on duty. You can visit the castle on your own. We got a headphone/interpreter so that we could listen to the explanations in German. An English version would be available, too. You got explanations of the place where you are currently, with some historic information. I mostly haven't listened to the whole explanations, they were too long.
There are also special events, like the medieval festival in May (unfortunately we missed it) and night visits of the fortress.
You will easily find the castle, there are enough signs that lead you to it. There is a free parking in front of the castle.
Opened from 10:00 to 18:00 (depending on season - better check their homepage at www.sedan-bouillon.com)
Admission: adults 6,90 Euro, children 4,60 Euro

Ruins of the abbey of Mont Dieu
Back at the village of Stonne from the Butte
Mostly mass graves in the days before dog-tags
Illy Cross stands atop Plain of Illy