Called Real Time Rome, the project paints a new picture of the ancient city: On seven large flexible glass screens and in fiery, fluorescent colors, Ratti and his team are able to show traffic congestion, the routes of the city's taxis and buses, and where city dwellers are congregating and moving—all with real-time wireless data.

"This new type of data provides an understanding of the city that we couldn't have had a few years ago," says Ratti, director of MIT's Senseable City Laboratory, which studies the impact of new technologies on cities. Wireless data, including that from GPS devices located on taxis and buses and aggregated, anonymous cell phone data from Telecom Italia, fuel databases that Ratti's team uses to create the topographies.

The stunning maps have been on display at the Venice Biennale art exhibition since September. During a Madonna concert this past summer, Ratti says he saw some of the "most beautiful patterns" on the screens. "You could see the city pulsating toward where the concert was," he says, "and how the infrastructure is really being used."

The project has both simple and grand goals. Simple, because Ratti sees benefits for citizens who want to avoid traffic jams and for emergency responders who need to see the most efficient routes. Grand, because "we can change the way we design cities," Ratti says. "It's a way to streamline movement in the city."

To that end, Ratti is launching the Senseable City Consortium, an R&D initiative to bring together public administrators, network operators, and hardware and software companies to design smarter urban environments. "Cities, in the past, were built out of concrete," he says. "Tomorrow, cities will be built out of silicon."