Montana

Montana Mines.   On this site you can explore photos and descriptions of mines and mine reclamation in Montana.  Numerous then and now photos explore cultural and architectural evolution of a number of major mining sites.  Also, click on Historical Narratives to learn about mining across the state.  From the state Department of Environmental Quality.
http://www.deq.state.mt.us/abandonedmines/index.asp

Historic Downtown Billings.  This site from the Yellowstone Preservation Board includes a page on the town's history, walking tours of historic downtown buildings, and photos.  [tdh]
http://www.yhpb.org/VirtualTours/BillingsTour/Map%20Page.html

Digital Atlases, Searchable Digital Archives, and Other Sites Useful for Exploring Places:

Western Montana Atlas of Panoramic Aerial Images.   A collection of medium-scale images across the state, including many that are rather spectacular, organized by county.  Created by William A. Bowen through the auspices of the California Geographical Survey at CSU Northridge.  [ccr] 
http://130.166.124.2/montana_panorama_atlas/index.html