Columbia subject headings:
Architecture--Spain--History--19th century.
Architecture--Spain--History--20th century.
Building, Iron and steel--Spain--History.
Harvard subject headings:
Architecture--Spain--19th century.
Architecture--Spain--20th century.
Building, Iron and steel--Spain--History.
Princeton subject headings:
Architecture--Spain--19th century.
Architecture--Spain--History--20th century.
Building, Iron and steel--Spain--Hisotry.