The cause of the power outage that severely disrupted life in Spain and Portugal on Monday remains a mystery as service was brought back to the Iberian Peninsula.

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

Millions were plunged into darkness in Europe on Monday as a massive power outage impacted parts of Spain, France and Portugal, but electricity was largely restored by Tuesday morning. The blackout wreaked havoc on travel across the three countries,