REMOVE

1. hats
2. rivers
3. shadows
4. monuments
5. benches (furniture)
6. barriers
7. 1969

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)