Tor Hidden Services (sometimes vilified as "The Dark Web") allows for offering services anonymously via the Tor network. Or provide an alternate to public IP addresses, where ISPs refuse to provide them.
The service choses some random "introduction points" from Tor's relays & builds circuits to them. We the client choses a random "rendezvous point", building a circuit to it.
We contact the service via the introduction point asking it to connect to our circuit via the rendezvous relay.
1/1.2!