San Francisco in 100 years

The year is 2108. Here in San Francisco, water is a precious resource and the population has doubled--or even tripled. How will the city accommodate these challenges? And what it's going to look like? That was the task eight architecture firms had to tackle in the History Channel's Future Cities Competition. CNET's Kara Tsuboi talked to some of the competitors about their vision for the City by the Bay in 100 years. And yes, there are robots and flying cars.