Spain Power Outage: Massive Blackout In Europe Largely Over

Huge Power Outage Strikes Spain, France, Portugal

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, and the impacts extended beyond there, too.

What We Know So Far:

-Most schools, offices and mass transit resumed Tuesday in Spain and Portugal.

- The cause of the blackout is under investigation, but officials with Portuguese energy company REN suggested that "due to extreme temperature variations in the interior or Spain, there were anomalous oscillations in the very high voltage lines (400 KV), a phenomenon known as 'induced atmospheric vibration,'" according to a BBC.com report. Spain’s Prime Minister Pedro Sánchez mentioned that a "strong oscillation" was behind the outage but said no conclusions about the cause could be determined yet.

- "No unusual meteorological or atmospheric phenomena were detected in Spain on April 28th, nor were there any sudden temperature fluctuations at our network of weather stations," said Spain's Meteorological Agency in a post on X.

(WATCH: Huge Tornado Derails A Train In Nebraska)

- Spain's parliament closed for the day Monday, and the Madrid Open tennis tournament postponed all afternoon and evening matches.

- The blackout cut power to some 50 million people in the Iberian Peninsula, according to the Associated Press.

(MORE: Ever Seen A Waterspout From A Plane?)

- The outage is not believed to be the result of a cyberattack.

- Spain was using electricity from France and Morocco to help get power restored to northern and southern parts of the country.

Images From Europe: