REMOVE

1. sky
2. shadows
3. artists (visual artists)
4. plants
5. rivers

WHAT

1. Visual Works (hierarchy n … (1)
2. arcades (structural assem … (1)
3. barriers (1)
4. benches (furniture) (1)

More 

WHERE

1. New York, New York (1)

WHEN

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