Thanks, Heidi, for posting, It is an interesting site, and adds another piece to the puzzle that is ancient Rome.
BTW, while I was there, my friend Laura showed me the coolest postcards in the gift shop - I had never seen these before, although perhaps others know them.
It's a kind of 3D card that, when you tilt it one direction it shows Piazza Navona (or the Colosseo or whatever the scene) as it is today; and when tilted another direction, the image becomes an artist's rendition of how the precise scene would have looked in its heyday.
I remember this style of postcard when I was a child, but cannot remember the proper name. Anyway, this is a cool way to "see" ancient sites!