Dutch sailor 'displaying' the Belgian method (not an actual method) of disposing of sea mines, 1939/1940?
The Dutch and the French both have many Belgian jokes (all along the lines that Belgians are dumb), but the funny thing is that many of the jokes actually originate from Belgium itself. They are jokes by the Flemish and Walloons making fun of each other that are then generalized to Belgians as a whole by the Dutch and French.
We still hold a bit of a grudge against them for having let the Germans pass without saying anything during WWII and also because they claim to have invented fries. We tease them but we still like them.