Columbia subject headings:
Harvard subject headings:
San Juan de Ulúa Island (Mexico)--History.
Veracruz (Veracruz-Llave, Mexico)--History.
Princeton subject headings:
Fortification--Mexico--San Juan de Ulúa Island--History--17th century.
San Juan de Ulúa Island (Mexico)--History--17th century.
Veracruz (Veracruz-Llave, Mexico)--History--17th century.