REMOVE

1. rivers
2. barriers
3. mountains
4. atmospheric perspective
5. trees

WHAT

1. Visual Works (hierarchy n … (1)
2. artists (visual artists) (1)
3. black-and-white film (1)
4. buildings (structures) (1)
5. bushes (1)

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WHERE

1. Westminster, Maryland (1)

WHEN

1. 1961 (1)
2. after 1961 (1)