The country’s top officials were trying to determine the cause of an outage that left tens of millions of people across the Iberian Peninsula without power.

Spain and Portugal switched their power back on after the worst blackout in their history, though authorities offered little explanation for what had caused it or how they would prevent it happening again.

Electricity is pulsing through Spain and Portugal again after a massive outage knocked out power in both countries on Monday. So too are questions.

The sweeping power outage that hit Spain and Portugal this week has raised questions about the electricity grid in a region not normally known for blackouts

An unprecedented blackout brought much of Spain and Portugal to a standstill Monday, stranding thousands of train passengers and