Fallen bridge: 'Stress test' preceded collapse that killed 6

MIAMI — An innovative pedestrian bridge being built at Florida International University had been put to a "stress test" and its cables were being tightened when it collapsed over traffic, killing six people and sending 10 to a hospital, authorities said.As state and federal investigators worked to determine how and why the five-day-old span failed on Thursday, one factor may have been the stress test that Miami-Dade Mayor Carlos Gimenez said crews were conducting on the span.Two workers we