Postcards
Here goes my 'small' postcards collection. Or actually small part of it, because I've stopped scanning them after reaching 750, but of course I'm still accepting them as a 'registration fee' for my Postcardware licensed software.
You can find here only scanned top sites of postcards, because often back sites contain sender address that few people may not want to show to others.
Postcards collection was originally part of my homepage, so everything is in my native language (Polish), but I believe you should easily find those country and cities name similar to your language or at least guess them :).
Postcards list
Total postcards: 750 from 39 countries