REMOVE

1. trees
2. dams (hydraulic structures)
3. between 1929 - 1960

WHAT

1. Visual Works (hierarchy n … (1)
2. bridges (built works) (1)
3. exterior views (1)
4. rivers (1)

WHO

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

WHEN

1. 1929 (1)
2. 1960 (1)