Spain experienced a widespread power outage that left millions without electricity for nearly a full 24 hours. While power has largely been restored, the cause of the failure is still under investigation.

Spain suffered several power glitches and industry officials sounded repeated warnings about the instability of its power grid in the build up to its catastrophic blackout on Monday.

A widespread power outage hit Spain and Portugal, affecting millions of people who live across Europe's Iberian Peninsula.