Just discovered Sepia Town, a wonderful new web site that lets you search, view and upload historical images by location, in order, as they put it, "to see what once stood where you now stand". Check out old photos and postcards of London, Paris, Amsterdam, Moscow, New York and San Francisco among other cities. The site has also added a Then and Now feature so that you can compare, say, Westminster Bridge from how it was in Victorian times to how it looks today. Another nice thing about Sepia Town is you can also get involved by adding your own vintage images to the site.