REMOVE

1. National parks & reserves.
2. Walking.
3. Library of Congress Prints a …
4. 1869-1942
5. between 1903 and 1906
6. 1903

WHAT

1. National parks & reserves … (1)
2. Nitrate negatives (1)
3. Photographs (1)
4. negative (1)

WHO

1. Genthe, Arnold (1)
2. Library of Congress Print … (1)

WHEN

1. 1906 (1)
2. between 1903 and 1906 (1)