The Google Cultural Institute is an amazing collection of images and documents curated by leading institutions around the world. The have partnered with Google to help bring these amazing works, some of which never see the light of day in their own facilities, to a global audience. Whether you teach history, art or math, there is something in here for everyone. The two videos below give an introduction to the online institute.
The first video will make you want to use the site.
This second video explains some of the wonderful offerings put forth by the Google Cultural Institute.