It's a tradition in Flanders to mark the start of the last one hundred days that pupils are at secondary school. In Tongeren, a town first settled by the Romans, pupils at the local school got a little carried away with themselves producing several devices that required the army's bomb disposal squad, DOVO, to attend the school.
The last year pupils succeeded in manufacturing several explosive devices. They claimed they have only made smoke bombs, but the school head was in no mood to take any chances and called in the armed forces.
Dovo took the bombs, each weighing one kilogram, to an open field called the 'Roman Cobbles' where it staged a controlled explosion.