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.

It may take a week for the network servicing both countries to be fully repaired. Meanwhile, millions are without power.

Millions across Spain, Portugal, and parts of France were thrown into chaos Monday after a massive power outage — blamed on a “rare atmospheric phenomenon” by some officials— crippled transportation networks,