Best documentary on WWI I've seen. Done in a week-by-week format (300 videos) and in bite size pieces:
https://www.youtube.com/playlist?list=PLB2vhKMBjSxMK8YelHj6VS6w3KxuKsMvT
https://www.youtube.com/playlist?list=PLB2vhKMBjSxMK8YelHj6VS6w3KxuKsMvT