Electricity is pulsing through Spain and Portugal again after a massive outage knocked out power in both countries on Monday. So too are questions.

The sweeping power outage that hit Spain and Portugal this week has raised questions about the electricity grid in a region not normally known for blackouts.

Electricity was restored to almost all of Spain and Portugal on Tuesday morning following a massive power cut affecting the entire Iberian Peninsula, but the cause of the blackouts remained a mystery.