REMOVE

1. hats
2. trees
3. sky
4. coats (garments)
5. automobiles
6. roads
7. portraits

WHAT

1. Visual Works (hierarchy n … (1)
2. artists (visual artists) (1)
3. black-and-white film (1)
4. branches (plant component … (1)

More 

WHEN

1. 1960 (1)
2. 1970 (1)
3. between 1960 - 1970 (1)