REMOVE

1. railroads
2. service stations
3. sky
4. machinery
5. buildings (structures)

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. exterior views (1)
4. fences (1)

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WHEN

1. 1920 (1)
2. 1940 (1)
3. between 1920 - 1940 (1)