One of the best known tools for historical information on Google Maps is a website called What Was There. Using this site, you can see still photos from different cities over the past century. Then, overlay them over the city’s modern street view.
Images are uploaded by individual users, so some areas are more populated than others. No matter how many images are available, this site is a great way to really feel connected with a city’s past and to gain appreciation for its history.
Google Maps for History