REMOVE

1. hats
2. machinery
3. sky
4. soil
5. workers

WHAT

1. Nespelem (1)
2. Visual Works (hierarchy n … (1)
3. automobiles (1)
4. black-and-white film (1)
5. buildings (structures) (1)

More 

WHERE

1. Nespelem, Washington (1)

WHO

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

WHEN

1. 1937 (1)
2. 1938 (1)
3. ca. 1937 - 1938 (1)