The Life Magazine photo archive is online now and hosted by Google. There are some amazing high quality photos from the last century, even ones from Rome and papal ceremonies. For instance, do a search for "Vatican" and you'll see some amazing pictures. The picture above is just one example (and that's the "small" picture).
LIFE photo archive hosted by Google
Note: Not all their photo descriptions are accurate. This picture is actually in Saint Paul's Outside the Walls, not Saint Peter's. And I've seen several that were at also labeled as being in Saint Peter's when they were actually in the Colosseum!