The allusion in the title of this story is to Psalms 137 in the Bible. You can see a link to it below.
This is a psalm in which the people of Israel are lamenting while they are being kept captive in Babylon. They are wishing that they could go back to what was once theirs.
If you think about it, John ends up like the Israelites. He finds out that there was this amazing civilization and that its people were the ancestors of John's people. He feels that his people have lost what was once theirs. He wants to get back to what his people used to have.
Now, this may be an ironic title. We are not at all sure that what John wants is going to be good for his people. He may be wishing for something that will end in disaster (they may just eventually end up like NYC already has ended up in the story).