The feature works on both the app version of Google Earth and the browser-based version. To access it, tap the layers menu. Below the option to toggle 3D buildings on or off, you should see a toggle for historical imagery.

For the service's 20th anniversary, Google was inspired by a social media trend from last year in which people shared historical images of locations in Google Maps. Now, Google Earth is getting a "time travel" interface where you can see historical Street View images from almost any location.

Google Earth is celebrating it 20 year anniversary. To commemorate the occasion, it's rolling out two new features.