The string-pullers learned long ago that there is no true need for thick stone walls or leaded vaults or complex locking devices. The security those methods provide is illusory at best. No, they understood that the best way to conceal any object at all is to simply hide it in plain sight.
Which is why you can find all of the answers if you know where to look.
There is a book. A thick, weighty tome with handwritten vellum pages, bound with a leather that was originally a bright blue but has since faded to dull gray.
The book rests on a high shelf, in a dim corner of a public reading room within the Richelieu Library building of the Bibliothèque Nationale in Paris.
It sits among similar-looking volumes, untouched and unexplored for decades or more. Just another morocco spine in a vast sea of anonymous folios.
If you look hard enough, and find that book, you can know everything. And you will understand why everything you know about the modern world is a lie.
That is, of course, if you know Latin. And can read Jacobean secretary script.