Columbia subject headings:
City walls--Germany--Dresden--History--Congresses.
Dresden (Germany)--Buildings, structures, etc.--Congresses.
Festung Dresden (Dresden, Germany)--History--Congresses.
Fortification--Germany--Dresden--History--Congresses.
Harvard subject headings:
City walls--Germany--Dresden--History--Congresses.
Dresden (Germany)--Buildings, structures, etc.--Congresses.
Festung Dresden (Dresden, Germany)--History--Congresses.
Fortification--Germany--Dresden--History--Congresses.
Princeton subject headings: