"True knowledge exists in knowing that you know nothing" is one of the foremost Greek philosopher Socrates's time-traveling quotes. It is quite accurately embodied in this interactive map featured, for your sonic bafflement, at Every Noise At Once.
I have been writing about music for a dozen years now, exploring from Middle Eastern folk to OPM and plain old street punk, on the way, but I still have a hard time putting schranz, swirl psych and iskelma into words. This map reminds me of how little I still know, but by clicking on each genre and subgenre I can now be lead to a more detailed sketch packed with each sound's representative names. The visual architecture also makes for an excellent memorisation technique - for more visual types, at least.
Knock yourselves out @ http://everynoise.com/engenremap.html.