In 09.2020 by pure chance I discovered the YouTube channel of Richard Borcherds where he gives graduate courses in Group Theory, Algebraic Geometry, Schemes, Commutative Algebra, Galois Theory, Lie Groups, and Modular forms! (and an undergraduate courses in Theory of numbers and Complex analysis).

I watched so far about 300 of his videos (about 90%) and they are really great. Borcherds is an amazingly good lecturer (for my taste). It is also clear, that these lectures were worked out/improved through years, since Borcherds was giving similar ones in Berkeley (one can find some lecture notes by students online). I would guess, that currently there are some other great lecturers that started to upload their courses on YouTube (or some other platforms). For this reason a question.

**Question.** If *you* watched recently an online graduate course (free for all), and found it brilliant, by a lecturer whom *you* find great, and believe that the course taught you something, could you please share the info about it.

The motivation for this question is to spread information about exciting things happening in mathematical life/education lately.