I am interested in the way scientific and mathematical subject areas developed (and are still developing). One of the great visual tools that can help us gain insight in how these areas developed is by creating a "genealogy".
For the case of mathematics: I already asked about it here (on Quora). Although there is a genealogy of mathematicians, (take a look over here), to my knowledge there is no such thing for mathematical subject areas. There are a few so-called "mind-maps" that show how some (certainly not all) mathematical areas are connected, but they don't take into account the historical developments that are relevant (another example is the Mathematical Atlas made by Dave Rusin, which unfortunately currently can't be viewed online).
So, to come back to the question: do you know of any (annotated) genealogies of scientific and/or mathematical subject areas? I think those can be great to help one gain a broad perspective on the history of science and mathematics, however crude it may be.