Heleen, on a short trip to Belgium from her native Netherlands, surprised me with this one. It might be my first Belgian stamp ever. It shows a Red Admiral butterfly, and has a symbol for 'world' rate (outside Europe, basically) with a built-in airmail indicator.
I love the little caterpillar she added to the envelope at a very early hour in the morning :) .
Inside were two postcards, one of castles, and one irregularly shaped like a serving of Belgian fries - I think that is mayo on the fries - which to me is disgusting, but to Belgians is clearly how it is done. I doubt it would have traveled all that well through the mail, so nice that it was in the envelope.