You can walk underneath the building where there is an archeological site. You can learn about the architecture from the middleages. Put on something warm when you go, because it is cold out there.
Le Conseil bruxellois des Musées a sélectionné un espace remarquable du Coudenberg, l'Aula Magna, qui est raconté depuis le site www.museumtalks.be au format MP3.