Power was gradually restored for millions on Monday following what Spanish officials called a "rare atmospheric phenomenon."

MADRID/LISBON (Reuters) -A huge power outage brought parts of Spain and Portugal to a standstill on Monday, grounding planes, halting public transport, causing panic buying and leaving the two countries scrambling to restore power to millions of homes and businesses.

BARCELONA, Spain (AP) — A blackout brought much of Spain and Portugal to a standstill Monday, halting subway trains, cutting phone service and shutting down traffic lights and ATM machines for the 50 million people who live across the Iberian Peninsula.