A massive power cut has affected at least two million people in Mexico and the American states of California and Arizona.
The outage occurred at about 3.40pm (local time) on Thursday.
It caused traffic chaos in several cities and forced California's two nuclear reactors to shut down, the BBC reports.
It started with a procedure by a lines company worker in an Arizona town that went wrong, causing a high-power line supplying electricity to Southern California to fail.
Minutes later, that led to a blockage that shut down California's San Onofre nuclear energy plant, a major source of power to the north of San Diego.
San Diego was the worst affected city, with all outbound flights cancelled, traffic at a standstill and scores of people having to be rescued from stalled lifts.
All trains were stopped in Los Angeles and traffic lights were knocked out in the Mexican city of Tijuana, causing chaos on the roads.
By early evening, crews had restored service in the section of the line that triggered the massive event and had begun to restore power to parts of San Diego County.