The Google Street View team has driven over 6 million miles over the last several years to collect imagery of the world around us. The Google Maps web application will now have a time machine feature so that users can move a slider to see historical images of a place.
Photos of the same place have been aligned so they have the same perspective as one another. Some locations may just have a couple versions, but other places like Freedom Tower in New York and the construction of the World Cup stadium in Brazil will have multiple photos.
The archived photos in Street View will be available in 55 countries where it is allowed. Germany will not have this feature because it only allows Google to post single images of 20 cities. This feature will be available on the desktop app version of Google Maps, but will be added to mobile devices later.