The menu at the top of every page has always held the full hierarchy, and it has always been the wrong instrument for it: a hover cascade is an index you cannot read, cannot print, cannot scroll back through, and cannot see at all without a pointer and a working script. This page is the same hierarchy standing still.
Everything the site serves is listed below. That is a claim with a mechanism behind it rather than a hope: the listing is generated from the pages that exist on disk, and the generator fails — it does not shrug, and there is no other bin at the bottom to sweep a page into — if any page is claimed by no part. A new page is findable here the day it is built, or the build stops.
Four parts hold it. The first three are the departments and carry the same contents on their own landing pages; the fourth is what the site uses on itself, and lives only here. A handful of pages are filed in one part and listed in another — a map is a map wherever it is kept — and those are marked cross-listed where they recur.
If you would rather see it drawn than read it: the Site Map is the same set of pages as a constellation, and the Changelog is the same set in the order it was made.