Columbia subject headings:
Harvard subject headings:
Architecture, Medieval--France.
Castles--France--History--To 1500.
Souterrains--France--History--To 1500.
Princeton subject headings:
Archaeology, Medieval--France.
Excavations (Archaeology)--France.
Fortification--France.
France--Antiquities.
Souterrains--France.
Underground areas--France.