Ah yes, the Khan academy. If you haven’t yet heard about Salman Khan’s mission to re-imagine education, then please have a look at this TED video.
Khan is quickly adding a lot of history videos. https://www.khanacademy.org/humanities/history/euro-hist
Khan’s best work is done in Mathematics, but I think that some students in some circumstances will get a lot out of the history videos.
Also be sure to check out the concepts of “flipping the classroom“.