REMOVE

1. garages
2. rock
3. trees
4. roads
5. windows
6. buildings (structures)
7. rubbish
8. barriers

WHAT

1. Visual Works (hierarchy n … (1)
2. artists (visual artists) (1)
3. benches (furniture) (1)
4. black-and-white film (1)

More 

WHERE

1. New York, New York (1)

WHO

1. Diane Still Knox; Diane K … (1)
2. Knox, Diane Still (1)

WHEN

1. 1958 (1)