Photos: San Francisco in 2108

Eight architecture firms tackle San Francisco in the History Channel's "City of the Future" contest. The firms envisioned, for example, how San Francisco will handle a limited water supply and double or triple the population in 100 years.

IwamotoScott Architecture, the winning design firm, created residential high-rise buildings that double as vertical algae-growing beds.

For video of the January 20 event, check out Kara's Tsuboi's report.