Spain and Portugal are racing the setting sun as they respond to a massive, unexplained power outage that knocked out traffic lights, caused chaos on roads and in airports, and threatened to plunge tens of millions of people into darkness on Monday.

A major power outage in Spain and Portugal has knocked out subway networks, traffic signals and ATMs. Spanish power distributor Red Eléctrica said resto

A massive power outage is affecting large parts of Spain and Portugal, including both countries' capitals, Madrid and Lisbon. Officials are investigating the cause of the blackout.