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

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.

Officials race to find cause of blackout as electricity returns to homes - More than 90% of power restored in Spain and Portugal as authorities try to find the cause of outage