Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom.
(Text taken from khanacademy.org)
John Green, author of The Fault in our Stars, teaches the history of the world in 42 entertaining crash courses.
In which author John Green teaches more world history based on topics like Money & Debt, War & Human Nature, and Disease!