The mechanical Carillon drum in the Ghent Belfort. The first Ghent drum dates from 1377 and was made of wood. After several iterations, the existing copper drum was installed in 1659! It is prepared to play 40 bells, which requires 17600 square holes to be drilled into the drum.
The drum is connected to the clockwork, which drives it every 15 minutes. During the rotation the pins touch the lifting levers at the top of the mechanism, which in turn cause hammers to strike the bells due to traction on the hammer wires.
The melody is changed every two years, just before Easter Sunday.