From the archaeological areas of Pompeii to the Hiroshima Peace Memorial, Google's World Wonders Project aims to bring to life the wonders of the modern and ancient world.
Another great resource for presentation software. It's got a fairly easy learning curve. I think it would be a great way for students to demonstrate learning.
This website provides free flexbooks on a variety of subjects. These are aligned with standards, and each resource is customizable. I was so excited to find this resource!
These are flipped TED lessons--a great resource for educators. Each video is professionally animated and narrated. Best of all, you can flip any YouTube video using TED Ed.