Columbia subject headings:
Historic districts--Cuba--Havana.
Historic districts--Ecuador--Quito.
Historic districts--Mexico--Mexico City.
Historic districts--Spain--Barcelona.
Harvard subject headings:
City planning
Historic districts--Conservation and restoration--Latin America.
Historic districts--Conservation and restoration--Spain.
Historic districts--Cuba--Havana.
Historic districts--Ecuador--Quito.
Historic districts--Mexico--Mexico City.
Historic districts--Spain--Barcelona.
Historic preservation
Princeton subject headings:
Historic districts--Cuba--Havana.
Historic districts--Ecuador--Quito.
Historic districts--Mexico--Mexico City.
Historic districts--Spain--Barcelona.