Columbia subject headings:
Architecture, Domestic--Italy--Tuscany.
Architecture, Medieval--Italy--Tuscany.
Buildings--Italy--Tuscany.
Fortification--Italy--Tuscany.
Towers--Italy--Tuscany.
Harvard subject headings:
Architecture, Domestic--Italy--Tuscany.
Towers--Italy--Tuscany.
Princeton subject headings:
Towers--Italy--Tuscany.