At least Europeans should be familiar with the “900 Days of Leningrad“, the siege by the German Wehrmacht which costs a lot of lives and destroyed most of the city. But they never gave up.
Sergei Larenkov, a Russian artist, found a lot of images from that time and took images from the same spot today. Digitally combined they have a strong impact.
You can find the collection at http://www.environmentalgraffiti.com.
For doing such a thing with an old image from your town you first have to find the spot and figure out the focal length of the lens (see comments). Then take the picture. My tip for stacking them would be Hugin, but I have never tried that. Then just mask parts of the top image and let the bottom one shine through.