Power has been restored to tens of millions of people across almost all of Spain and Portugal, but disruptions to transport services were expected to stretch into a second day as questions mount over what caused a massive blackout.

BARCELONA, Spain (AP) — A blackout brought much of Spain and Portugal to a standstill Monday, halting subway and railway trains, cutting phone service and shutting down traffic lights and ATMs for millions of people across the Iberian Peninsula.

A widespread power outage hit Spain and Portugal, affecting millions of people who live across Europe's Iberian Peninsula.