In the centre of town lies the Unesco-listed Beffroi, a medieval stone fortress tower on which a clock spire was plonked in 1733. It houses a youth information centre and can't be visited.
The pockmarked facade of the belfry and the adjoining building attest to a devastating bombing raid in WWII, when American planes 'accidentally' bombed the city centre, killing 330 and gravely injuring 600 residents.