CNBC — Building the city of the future — at a $41 trillion price tag

Cities around the world could spend as much as $41 trillion on smart tech over the next 20 years.

"But, but, where will the money come from?"

That's going to take a whole lot of electricity, too.

CNBC
Building the city of the future — at a $41 trillion price tag
Aneri Pattani, special to CNBC.com