Columbia subject headings:
Harvard subject headings:
Cities and towns--Portugal.
Fortification--Portugal
Islamic architecture--Portugal.
Portugal--Antiquities.
Princeton subject headings:
Architecture, Medieval--Portugal--Pictorial works.
Architecture, Medieval--Portugal.
Castles--Portugal--History.
Castles--Portugal--Pictorial works.
Fortification--Portugal--History.
Fortification--Portugal--Pictorial works.
Islamic architecture--Portugal--Pictorial works.
Islamic architecture--Portugal.
Portugal--Description and travel.