The Mundaneum sounds like a Borgesian conceit. While the author's Library of Babel contains every book ever written, and every book that could ever be written in the future, the Mundaneum was nothing less than an attempt to archive and catalogue all of the world's knowledge on paper. Talk about mildly ambitious.
The brainchild of a pair of Belgian idealists, the Mundaneum was conceived as a means of promoting European and global unity and peace. Relocated from Brussels to Mons, it's now a museum and intellectual and cultural hub, and remains true to its founders' aims. Well worth a visit, I'd imagine.