REMOVE

1. rock
2. sky
3. benches (furniture)
4. shadows
5. rivers
6. plants

WHAT

1. Visual Works (hierarchy n … (1)
2. artists (visual artists) (1)
3. branches (plant component … (1)
4. buildings (structures) (1)

More 

WHERE

1. New York, New York (1)

WHEN

1. 1964 (1)
2. ca. 1964 (1)