Did you remember? Photography is documentry!
How does life looked back in the 50ies? We know it from thousands of photos taken in this decade. And there are also thousands of different perspectives. Tourists just do their "I was here" thing showing future generations how a typical vacation looked back in this specific time and place etc. Photographers add some concepts, art, a story and other things to the great visual diary of the world. Things around us are changing very fast and a house is demolished in just a few days and the whole street-view looks different over night. But from older photos we know how it looked like the day before. So don´t forget. You are also adding your view to the visual records of history.