Built in the 11th century on a spur blocking the valley of the Hoëgne, Franchimont Castle, the residence of the castellan then governor of the marquisate, has imposing ruins which are worth a visit. Built around a rectangular courtyard, the original fort is still quite visible and was made up of three wings of buildings pierced with arrow slits (with a fine vaulted room to the north) and in the east, a massive keep measuring 11 metres by 13 metres, with walls 3 metres thick at the base.

 

In the 13th and 14th centuries, the keep was flanked with buildings at an angle and, in 1387, the whole east side - the most vulnerable side - was defended by defences made up of two turrets and a full spur, whereas the entrance was protected by high walls. Under Erard de la Marck (1505-1538), the fortress was adapted to artillery fire. A high pentagonal wall, 5 to 6 metres thick, and 264 metres in circumference, protects the original nucleus. Circular blockhouses (three are accessible) with cannon emplacements flank four corners of the wall, whereas on the north-east side, a large reinforced artillery tower (26 metres in diameter) protected the entrance. A chapel, latrine tower, bread oven and a well over 60 metres deep can all still be seen. Since the 16th century, the castle has not been subject to any alterations and this is why it remains a rare example of a 16th-century fortified castle.