Capital city is Brussels. Belgium can be divided in two parts that are in many ways completely different from each other. As already mentioned, caves are located in the Southern part of the country. Of course, even impenetrable sinkholes were counted as well. 150 kilometers of underground galleries.
Belgian caves have a reputation of being muddy and narrow.
Yes, we do have some muddy caves, but no more or less than in any other caving country. Belgian caves have been under enormous pressure over the last decades. Of course, if the club agrees to accompany you in the cave, there is no problem at all. Very often they can be visited, but of course after having asked permission.