A massive power outage appears to have affected large portions of Spain and Portugal Monday.

BUDAPEST, Hungary (AP) — An unprecedented blackout across Spain and Portugal upended the lives of millions across the Iberian Peninsula, a stark reminder of modern society’s reliance on electricity, and how quickly life can descend into chaos when the grid goes down.

Spain's investigation into the power outage that blacked out the entire Iberian Peninsula this week continued Thursday as top security officials met Wednesday.