I was looking across one website recently. It contained images where through photoshop images from World War II were combined with modern images of the exact same location.
The result is eerie. It reminds us of how streets and locations were occupied in the past by other people and what may seem today a quiet suburban street may have been a location of bloodshed and war.
I am a history fanatic so I have always have that sense of being able to remember every location has a past and previous generations walked on those same roads, may have entered the same buildings, stood at the same bus stops or how a century ago a particular street was for people then as much a part of a living city as it is today for us, but a lot of people struggle to see that.
These images remind us that 'our' streets were once used by others and 'our' houses were once someone else's. And they remind us that at times those streets had witnessed experiences a million miles from our experiences.
Another website (I haven't got the link here unfortunately) shows San Francisco and combines the modern city with the effects of the earthquake. One eerie picture shows a man standing by his car on the street. All around the car is an image from that exact spot of the earthquake, showing dead horses killed by rubble.
Past and Present Collide in Ghosts of War, France - My Modern Metropolis (Unfortunately I cannot make the images show up on this page but follow the link to see them.)