Columbia subject headings:
Harvard subject headings:
Castles--Europe--History--Congresses.
Castles--France--History--Congresses.
Water and architecture--Europe--Congresses.
Water and architecture--France--Congresses.
Water-supply--Europe--History--Congresses.
Water-supply--France--History--Congresses.
Princeton subject headings:
Castles--France--History--Congresses.
Water resources development--France--History--Congresses.
Water-supply--France--History--Congresses.