A country that keeps its best rooms behind plain doors and does not think this requires an explanation.
One entry, and I will not pad it. This directory keeps houses and workshops I have actually walked through, and in Belgium that comes to a single address in Antwerp. It is, in fairness, an address worth the whole country's shelf space.
The distances here are absurd in the best way. Antwerp to Brussels is three quarters of an hour on a train that runs constantly; Ghent and Bruges are nearer still. Base yourself in one city and treat the rest as afternoons.
Monday closing is the rule rather than Tuesday, which catches out anyone arriving from France. Check the day before you buy the ticket, not the morning you plan to use it.