REMOVE

1. girls
2. boys
3. sitting
4. doors
5. buildings (structures)

WHAT

1. Niagara Falls (waterfall) (1)
2. Visual Works (hierarchy n … (1)
3. artists (visual artists) (1)
4. black-and-white film (1)
5. eyeglasses (1)

More 

WHERE

1. Niagara Falls, Ontario, C … (1)

WHO

1. Campbell, Sandra L. Still (1)
2. Sandra L. Still Campbell; … (1)

WHEN

1. 1964 (1)