Mathematical Visual Proofs is exactly what it says on the tin, a collection of videos (either with spoken voice or wordlessly with animation) explaining mathematical concepts from the basic to the complex. They are incredibly clear and easy to follow.
A few samples worth watching:
Top Ten Epic Pythagorean Proofs Without Words
Factor a Sum of Two Cubes (visual proof without words)
Beautiful Geometry behind Geometric Series (8 dissection visual proofs without words)
But this is my current favourite: