"A solid resource for math and science instruction as well as foundational knowledge in a number of other high school subjects." Great, best resource for additional video clips of explaining math concepts.
"As you can guess from its name, it provides crash courses on multiple subjects. Currently, students can find courses on world and European history, Physics, Philosophy, Psychology, Literature, Media Literacy, Astronomy, and many many more. Playlists usually include over 40 videos, which start from the basics and move on to more advanced material as they progress."