260milion people cannot be wrong.
Khan Academy is a non-profit educational website created in 2006 by educator Salman Khan, a graduate of MIT and Harvard Business School. The stated mission is to provide “a free world-class education for anyone anywhere”.
The website features 700 micro lectures via video tutorials stored on YouTube teaching mathematics, history, healthcare, medicine, finance, physics, chemistry, biology, astronomy, economics, cosmology, organic chemistry, American civics, art history, macroeconomics, microeconomics, and computer science. Khan Academy has delivered over 260 million lessons
Although delivered with an American lilt, the subject matter and concepts cross boundaries