This is a terrific photo that we dug up on Flickr. It shows Union Station under construction in the early 1900s. We also cross-posted this on Ghosts of DC.
Taken by Sidney Duff in Washington, DC. Union Station was completed in October 1908. Here, only one of the six statues have been installed over the entrance. Another photo from the set shows the Tidal Basin frozen over, causing me to guess that this is January 1908.
Source: Rob Ketcherside