Had wondered about this building in my neighborhood, specifically in precisely what sense it was the "Home of 7up." First time I tried to get the internet to explain it to me it failed, but fortunately the internet has become smarter since then. Apparently the stuff was first made in St. Louis, was marketed as a hangover cure, and contained lithium citrate to stabilize your mood. Someone in Philly licensed the formula and set up the first bottling company.
Now you know.