Sergey Larenkov is an amateur photographer who collects old wartime postcards and had the idea of combining them with modern day photos. He spends time researching the exact place where the wartime photographer stood to take the shot, so that he can line up his modern day photo to match it, then uses Photoshop to meld the two together.
It's like looking at ghosts.
It's a reminder that the past is all around us, we are enmeshed in history whether we like it or not. Where we are walking, stuff happened - good, bad, beautiful, horrific, mundane or of world importance - it occurred, right here. Do click on the pictures to make them bigger and get the full details:
You can see more of the pictures at Sergey's blog
Jo Teeuwisse has done something similar with pictures from Amsterdam:
You can read more information about her work here. (My Modern Met - where I found all these pictures in the first place - is fast becoming one of my absolute favourite websites. It says it's a site "where art enthusiasts and trendspotters connect over creative ideas" which is a very Hipsterish thing to say and hence open to ridicule but I'm constantly in awe of the photography and art that is featured there.)