The University of North Carolina @ Chapel Hill has recently placed online a collection of photographs from Hugh Morton, noted photographer and nature conservatist. The collection can be found online at http://www.lib.unc.edu/dc/morton/index.html.
The online collection only represents a portion of the collection available at UNC, but there are a few pictures online of George Washington Vanderbilt’s Biltmore Estate.
I particularly like this aerial view.
You can view the others in the collection here.