REMOVE

1. buildings (structures)
2. roads
3. clouds
4. trees
5. artists (visual artists)
6. sky

WHAT

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

More 

WHO

1. Campbell, Sandra L. Still (1)
2. Sandra L. Still Campbell; … (1)

WHEN

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