Power outages disrupted daily life and left millions of people in the dark. Tens of millions of people on the Iberian Peninsula had their Mondays upended by power outages that lasted hours.

A countrywide power outage impacted Spain—as well as swaths of Portugal and smaller portions of France—Monday afternoon, affecting essential services and wreaking chaos across the Iberian Peninsula. The cause of the outage is currently being investigated by Spanish and Portuguese officials and ministers.

A massive power outage is impacting Spain and Portugal, knocking out key services and forcing the evacuation of subway systems in both countries, reports say.