REMOVE

1. automobiles
2. plants
3. barriers
4. platforms (general)

WHAT

1. athletes (1)
2. black-and-white film (1)
3. horses (animals) (1)
4. men (male humans) (1)
5. polo (field sport) (1)
6. polo clubs (built complex … (1)
7. polo fields (1)
8. sky (1)
9. spectators (event observe … (1)
10. sports uniforms (1)
11. trees (1)
12. Visual Works (hierarchy n … (1)
13. woods (plant communities) (1)

WHERE

1. Aiken, South Carolina (1)

WHO

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

WHEN

1. 1966 (1)