Columbia subject headings:
Architectural drawing--Spain.
Palacio del Congreso (Madrid, Spain)
Spain--Capital and capitol.
Harvard subject headings:
Architectural drawing--Spain.
Architecture, Modern--19th century--Spain--Madrid.
Madrid (Spain)--Buildings, structures, etc.--Designs and plans.
Palacio del Congreso (Madrid, Spain)
Spain--Capital and capitol.
Princeton subject headings: