Mitt Romney was at his New Hampshire vacation home on a summer night in 2006 when 26 tons of concrete ceiling panels in one of Boston's Big Dig highway tunnels collapsed. The debris crushed a car and killed a female passenger.
Romney, then in his final year as Massachusetts governor, dashed back to Boston and immersed himself in the crisis.
His response offers insights into what kind of leader the expected Republican nominee would be if elected president. Romney has made his management skills a major selling point in his campaign.
Yet Romney's stiffest leadership test as governor produced mixed results.
He was praised, even by some Democrats, for his energetic, take-charge management style. But he also drew criticism for playing to the media and dodging personal blame.