Bridge Collapse Still a Mystery

State and private experts are investigating the wreckage of the I-35W bridge in search of a structural explanation for Wednesday's collapse, and sophisticated computer modeling is testing stress points. Time looks at bridges, seemingly indestructible structures that carry enormous volumes of traffic and can succumb to anything from corrosion to a faulty component the size of a pin.

Meanwhile, divers inspected four submerged vehicles and identified a fifth today, finding no victims, the Star Tribune reported. The death toll reached five and is expected to climb, but the number of missing people was revised sharply downward to eight. And in Washington, the House unanimously approved $250 million to rebuild the bridge. (More bridge collapse stories.)