Google Life Archive is a wonderful resource of historical images. It features millions of searchable photographs from the Life photo archive stretching from the 1750s to the present day. Most of these images were never published and are now available for the first time through the joint work of Google and Life magazine.
As a teacher, you can use this resource to search images to include in your work and you can also introduce it to your students and show them how to search its database for images to use in their presentations and projects especially knowing that these images are public domain. No worries about copyright issues .
Google Life Archive is completely free and and easy to use. It also has a user friendly interface with images organized into different categories. Images are searchable by decade as well as event. I was looking into the archive of the 80s and it is really amazing. I ll let you explore this awesome resource and don`t forget to share with us your feedback.