A page to get lost in: American Environmental Photographs from the University of Chicago library (U of Chicago was one of the top schools in the early days of ecology).

somehow, field trips seem more romantic when all the students are dressed in jodphurs and high-laced boots.

There are some great old atmospheric black and white photographs of places like Lake Superior and prairies in Oklahoma.

And more:

Historical Panoramic Photographs (and apparently, it's possible to order reproductions if there's one you particularly fall in love with, but it doesn't say how expensive they are).

The evolution of the conservation movement (I may have linked to this before; it's more of a multimedia history of the U.S. Conservation movement, but it has neat old pictures too).

Photographs of the Northern Great Plains.

The Ohio River Valley

Heck, those are just a couple reflecting my personal interests. You can go to the Collection Finder and look yours up. (I tried typing "knitting" into the search box but didn't get anything back that specifically looked like it contained knitting. But you are welcome to try.)