REMOVE

1. railroads
2. mountains
3. cranes (equipment)
4. barriers
5. houses
6. Balliett, Whitney

WHAT

1. Visual Works (hierarchy n … (1)
2. black-and-white film (1)
3. branches (plant component … (1)
4. close-up views (1)
5. doors (1)

More 

WHERE

1. Westminster, Maryland (1)

WHEN

1. 1961 (1)
2. after 1961 (1)