REMOVE

1. plants
2. buildings (structures)
3. moustaches
4. stairs

WHAT

1. Visual Works (hierarchy n … (1)
2. beaches (1)
3. black-and-white film (1)
4. bushes (1)

More 

WHERE

1. Ensenada, Baja California … (1)

WHO

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

WHEN

1. 1949 (1)