Learning about – Foundations of Mathematical Physics
Professor Frederic P. Schuller, from the Friedrich-Alexander University, has his unique signature written all over his lectures. They are precise, fast paced, detailed, and simply great. Amazingly he publishes his recorded lectures on his YouTube channel, and I can recommend browsing its content without any particular goal in mind. But more specifically, I recommend his lectures on the foundations of Mathematical Quantum Physics. Click below, if you have the time to watch his more detailed introduction to logic, set theory, topology, manifolds, and onwards.
Or perhaps that is too many details before getting into useful stuff. Then I can recommend this speed up version, from a winter school in 2015.