As the lights flickered on in New York and half a dozen other major North American cities today, the fingers started pointing over who or what was to blame for the most serious blackout in the continent's history.
Some 20 hours after the power went out, officials were still scrambling to pinpoint just what caused the cascading failure of the electricity grid from Maine to the Great Lakes.
A growing chorus of experts suggested that the massive power failure was a disaster waiting to happen because the creaking energy infrastructure that serves the United States and Canada - built on 1950s technology - has been all but overwhelmed by huge increases in the power volume flowing through the grid.
PresidentGeorge W. Bush called blackout a "wake-up call" and said he would push toupgrade the nation's electricity grid to head off futurebreakdowns.
Former Energy Secretary Mr Bill Richardson, now the governor of New Mexico, summarized it succinctly: "We're a superpower with a Third World grid," he said.
As Toronto and Ottawa were plunged into darkness, the office of Canadian Prime Minister Jean Chretien issued several early explanations for the power loss that turned out to be wrong, and later asserted that a Pennsylvania nuclear power plant outage may have caused it.
Power grid operators were less precise, saying only that there appeared to have been a failure in the high-voltage transmission lines connecting the United States and Canada.
"How did this happen, why did it happen and why did we have a systemic failure across the power grid in the northeast when we were told after the blackout in the 1960s that this would not happen again?" demanded New York Governor George Pataki.
Mr Pataki said the New York Independent Systems Operators were certain the outage occurred west of Canada's Ontario province and cascaded from there into the northeastern United States.
Apart from the scale of the blackout, which eclipsed one in 1965 that affected about 30 million people, the wildfire-quick spread of the outage exposed a fundamental vulnerability in the grid not contained by advanced computer systems.
"I view this as a wake-up call," President George W. Bush said in California, referring to the electricity grid as "antiquated" and acknowledging it needed to be modernized.
Most Americans and Canadians appeared to take the blackout in their stride with many expressing relief that it was not caused by an act of terrorism. Still it has been a humbling experience for the world's only superpower, which is still struggling to restore electricity in Iraq, nearly four months after the end of the war that toppled Saddam Hussein.