Spain and Portugal are reeling from a massive, unexplained power outage that knocked out traffic lights, caused chaos on roads and in airports, and prompted both countries to declare a state of emergency.

A blackout has brought much of Spain and Portugal to a standstill, affecting millions of people. The Spanish power distributor calls it “exceptional and extraordinary."

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