Columbia subject headings:
Canals--Italy--Venice--History.
Canals--Italy--Venice--Maintenance and repair.
Canals--Italy--Venice--Pictorial works.
Hydrology--Italy--Venice.
Venice (Italy)--Pictorial works.
Venice (Italy)--Threat of destruction.
Harvard subject headings:
Canals--Italy--Venice--History.
Canals--Italy--Venice--Maintenance and repair.
Canals--Italy--Venice--Pictorial works.
Hydrology--Italy--Venice.
Venice (Italy)--Pictorial works.
Venice (Italy)--Threat of destruction.
Princeton subject headings:
Waterways--Italy--Venice.