We've already seen China build subdivisions, a mall, amusement park, a university and more, all sitting (essentially) empty so what is next? For your consideration, this McKinsey video where their research shows that over the next 10 years, China plans to spend tens of billions of dollars building thousands of kilometers of metro lines to connect 35 cities (I wonder how many of those are currently ghost cities) which will not only transport people, but enormously improve efficiencies on shipment of goods.