A long time ago, between 1890 and 1900 thousands of photochroms/photolithographs were published with sceneries from all over Europe. In 1985 The Library of Congress bought the prints of Europe and the Middle East from the Galerie Muriset in Switzerland. Now everything is available on flicker. Addional collections can be found here. Usually one have to buy collections like this on DVD but now its free on flickr.
There are many photos of my hometown Bergen in the collection, I love to study them and compare old with new to see how the city has developed. Check out these lovely ones :
The last one is something I took last August, do you see where it is on the old photos? 🙂 Wish I had something better to compare though. For now only Scandinavian countries have been published on flickr but they are moving further and further into Europe these days.