I'm a bit late to this party (it being 2022 and all), but I took a stab at putting together a high-level explanation of what blockchains are how the blockchain works.
https://www.youtube.com/watch?v=X7_uZog6arkIt's based on a recent talk I gave at Elementus, which was well-received enough for me to think that it would be of broader interest.
I provide a big-picture definition of the blockchain drawn from sources like Andreas Antonpolous, how transactions are validated, broadcast, and structured, how blocks are created from the mempool, what mining is and why it's important, and how the whole network maintains security.
All this with multiple Harry Potter analogies, if you're into that kind of thing.
Posting here because I'd like to know whether these explanations resonate and whether I got anything factually wrong.