REMOVE

1. buildings (structures)
2. horizon line
3. roads
4. railroads

WHAT

1. Visual Works (hierarchy n … (1)
2. exterior views (1)
3. fences (1)
4. fields (land) (1)

More 

WHERE

1. Killam, Alberta, Canada (1)

WHO

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

WHEN

1. 1920 (1)
2. 1945 (1)
3. between c. 1929 and c. 19 … (1)