As a kid I became obsessed with the Official Handbook of the Marvel Universe and Who's Who in the DC Universe, not so much because of the character entries (the former far more exhaustive than the latter) but because of the headquarters floor plans: Avengers Mansion, the Justice League Satellite, the Baxter Building, Challengers Mountain, Avengers Compound -- heck, even the Serpent Society headquarters.
It didn't matter whether I knew much of the characters (the Challengers of the Unknown) or didn't care about them (the Serpent Society, really?), I'd pore over them by the hour. (I bought Mayfair's New Teen Titans role-playing game just for the plans to Titans Tower; never did play it.)
What started me on that trip down memory lane are the incredible plans and cross-section drawings of Key House that Gabriel Rodriguez has been has been posting on Twitter the past few days. They're destined to become end sheets for the Lock & Key: Alpha & Omega hardcover, but they could easily stand alone in their own book. They're just that beautiful and meticulous (you can see more on Rodriguez's Twttier under "#Keyhouse").
You'll have to wait a while to see them in print: The Lock & Key: Alpha & Omega hardcover arrives in February from IDW Publishing. In the meantime, I need to unearth those tattered copies of Who's Who and OHOTMU ...