REMOVE

1. railroads
2. rock
3. buildings (structures)
4. hills
5. landscapes (representations)
6. 1937

WHAT

1. Greenwich, Connecticut (1)
2. Visual Works (hierarchy n … (1)
3. black-and-white film (1)
4. bushes (1)
5. dogs (animals) (1)

More 

WHERE

1. Greenwich, Connecticut (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1956 (1)
2. 1956 April 11 (1)