Description: The fortress of Billy has been built in the 12th century : it had military functions and has been a part of the Lords of Bourbon's patrimony for a long time.
You could notice the main surrounding wall, wich is oval, and the hexagonal watch-tower. This one overlooks the medieval houses ans streets, wich coil up around the castle. The entrance is still very imposing. If you walk along the south surrounding wall, you have a magnificent panoramic view of the Allier valley