REMOVE

1. rock
2. barriers
3. paths
4. valleys (landforms)
5. soil

WHAT

1. banks (landforms) (1)
2. black-and-white film (1)
3. bridges (built works) (1)
4. buildings (structures) (1)
5. construction equipment (1)
6. construction sites (1)
7. cranes (equipment) (1)
8. fences (1)
9. Grand Coulee Dam (dam) (1)
10. hills (1)
11. landscapes (representatio … (1)
12. machinery (1)
13. mountains (1)
14. rivers (1)
15. roads (1)
16. rubbish (1)
17. scaffolds (1)
18. sheds (storage structures … (1)
19. sky (1)
20. Visual Works (hierarchy n … (1)
21. wood products (1)

WHERE

1. Grand Coulee, Washington (1)

WHO

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

WHEN

1. 1936 (1)
2. 1937 (1)
3. ca. 1936 - 1937 (1)