This was my first ever look at mesh networks, years ago!! Met a bunch of people hacking on it in c-base. Those guys are awesome! And my go-to example for large successful installations of CJDNS over wireless mesh (40k+ nodes AFAIK!). Also I'm under the impression that Freifunk consider themselves part of Hyperboria, but I'm not so sure actually...
People are usually impressed just looking at the network map https://www.freifunk-karte.de/