NYPL has an extensive digital collection, and I came across a Mugnier stereo of the Lee Monument:

Mugnier Photos stereogram of the Lee Monument, 1880s.

Mugnier Photos stereogram of the Lee Monument, 1880s.

Now, what’s particularly cool about the NYPL site is they have a utility called the “Stereogranimator” that simulates the 3D effect you’d get looking at one of these cards with a 3D viewer. It’s kind of neat:

GIF made with the NYPL Labs Stereogranimator - view more at http://stereo.nypl.org/gallery/index
GIF made with the NYPL Labs Stereogranimator

This is quite interesting, and I’ll see what else they have in their collections.