Power was gradually restored for millions on Monday following what Spanish officials called a "rare atmospheric phenomenon."

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.

The massive power cut that stranded Mr Hughes triggered chaos across Spain and Portugal, and also impacted Andorra and parts of France, from about midday local time (10:00 GMT). Traffic lights shut off. Metros closed. Businesses shuttered and people joined queues to get cash as card payments did not work.