REMOVE

1. tunnels
2. rock
3. silver gelatin
4. mountains

WHAT

1. Visual Works (hierarchy n … (1)
2. exterior views (1)
3. landscapes (representatio … (1)
4. roads (1)

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WHERE

1. Alberta, Canada (1)
2. Pacific Northwest (1)

WHO

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

WHEN

1. 1920 (1)
2. 1945 (1)
3. between circa 1929 and ci … (1)