Sure, you got a great education from top schools, and you've been working for awhile now. But as you get deeper and deeper into your career, it can become easy to stop pushing yourself to acquire new skills or retain what you've already learned.

The Khan Academy, an online learning nonprofit backed by powerful investors and organizations like the Gates Foundation and Google, is a great way to keep expanding your knowledge, regardless of your age or educational background. The site features hundreds of free courses across a wide variety of subjects, consisting of video lectures and exercises.

We asked Salman Khan, founder, executive director, and lead tutor of Khan Academy, for the top 10 lectures professionals in any industry would appreciate, and included them below.

Not every lecture is the first one in its respective series, but Khan thinks each is a good indicator of whether you'd like to spend more time going through all the videos and exercises in that course.