Charles O. Paullin and John K. Wright's Atlas of the Historical Geography of the United States. First published in 1932. This digital edition developed at the University of Richmond's Digtial Sholarship Lab reproduces all of the atlas's nearly 700 maps. Thanks to the Belfast Telegraph for making the video embeddable. Why the University of Richmond did not is unclear.
Many voices chime in to answer the question “How does one find existing services that implement OGC Web Map Service (WMS), Web Feature Service (WFS), and Web Coverage Service (WCS) interface standards these days?”