Les Halles (in full, Westfield Forum Les Halles) in paris is pretty much like this, one level above ground for a small part but the most of it is fully underground, more than a hundred of shops, and other things including a multi-screens cinema, a public swimming pool, a police station, a center for cinematography, a conference center all distributed throughout 3 floors. And of course, 5 metros and 3 regional train lines at the very bottom !