It started with some Pittsburgh humor. Pittsburgh-based comedian Tom Muisal does a bit about a GPS unit that can give directions in “Pittsburghese.” Because in Pittsburgh, no one calls it “Interstate 376,” it’s “The Parkway.” It’s not “The Liberty Tunnel,” it’s “The Liberty Tubes.” And directions are often given by way of what used to be there. One day Tom was trying this routine out on his friend, Mike Neilson. Mike is not from Pittsburgh—he grew up on the other side of the state. When he moved to the Steel City, he had a hard time figuring out how to get around. Because Pittsburghers are always telling him to turn left at something that isn’t there anymore. And then, as Mike was listening to Tom’s Pittsburgher GPS routine, he noticed that in in one iteration of the joke he said, “turn left at the place that used to be a Pizza Hut.” This resonated with Mike. He realized that, because the architecture of a Pizza Hut is so distinctive, he could easily identify any building that used to be a Pizza Hut. The former Pizza Hut was thus a beacon of light shining through a thick fog of impossible directions. Here, in his friend’s comedy routine, was the one Pittsburghese direction he could give that anyone, regardless of where they’re from, could comprehend: turn left at the place that used to be a Pizza Hut. And from there, Mike created a global atlas of all the places that used to be Pizza Huts.