Rephotography is the act of repeat photography of the same site, with a time lag between the two images; a “then and now” view of a particular area. Some are casual, usually taken from the same view point but without regard to season, lens coverage or framing. Some are very precise and involve a careful study of the original image. Long a technique for scientific study, especially of changing ecological systems, it became formalized as a form of photographic documentary in the middle 1970s.
Could you find an old postcard or other photograph of your town, street or some area and create a ‘then and now’ rephotograph? I think getting the position just right would be tricky and take some real patience, likely several practice shots before you could hit it just right.
Other places to find rephotography:
Flickr: Now and Then
Flickr: BBC Turn Back Time
Flickr: Paris Then and Now
Flickr: Vancouver “Then and Now”
Thomas May Photography: Then and Now
Retronaut: Rephotographing St. Petersburg
Wired: Gadget Lab: Camera Software Lets You See into the Past
Web Designer Depot: Then and Now Portrait Photography by Irina Werning
Fourmilab: The Craft of “Then and Now” Photography