Columbia subject headings:
Harvard subject headings:
Lisbon (Portugal)--Buildings, structures, etc.--History.
Praça do Comércio (Lisbon, Portugal)--History.
Public spaces--Portugal--Lisbon--History.
Princeton subject headings:
Lisbon (Portugal)--Buildings, structures, etc.
Plazas--Portugal--Lisbon--History.
Praça do Comércio (Lisbon, Portugal)--History.