FORTIFIED CASTLE

For a thousand years, a keep has dominated the valley, the last vestige of a construction that covered almost 17 hectares. Beneath the remains, visitors stroll through the maze of vaulted rooms, stop off in an artillery gallery and venture into the mysterious, superbly restored underground passages. Several construction campaigns stand out: an Ardennes sandstone fortress built in the late ^12th century, incorporated into a brick fortress in 1540. Wear good shoes and bring a woollen jacket to descend into the underground passages!