WhatWasThere has made it easy for people around the world to contribute to a project where images of the past can be superimposed over images from today (using Google Street View). WhatWasThere's objective is to create "a new human experience of time and space – a virtual time machine of sorts that allows users to navigate familiar streets as they appeared in the past."
Go to WhatWasThere and search by your city (e.g., Crawfordsville, IN) or zip code (e.g., 47933) to see some of the images that the Reference/Local History staff have already added. We have just a handful at this time but plan to keep adding! Where do we get our "old" pictures? Well, we use our ever-growing Image Database to find past views that we know we can place with current views.You are welcome to help us, too, if you wish to get a free account with WhatWasThere.