I’ve seen quiet a bit of work like this where images of the same location at different times are merged into a single image. These two images are by Russian Photographer Sergey Larenkov, and I think work really well.
Sergey’s site is http://sergey-larenkov.livejournal.com/ and he has been featured here also: http://www.dailymail.co.uk/news/article-2116708/Russian-troops-storm-Reichstag-Extraordinary-images-merge-images-European-city-streets-war-peace.html
