Power had almost fully returned to Spain early Tuesday morning as many questions remained about what caused one of Europe’s most severe blackouts that grounded flights, paralyzed metro systems, disrupted mobile communications and shut down ATMs across Spain and Portugal.

Officials for the Madrid Open cancelled Monday's play amid a blackout in Spain that impacted the tournament's facilities. The blackout caused a number of logistical problems at Caja Mágica with the scoreboards going dark and the loss of lighting to help fans navigate the venue:

Power is being restored to cities across Spain and Portugal after a major outage. Flights, traffic lights, trains and phone networks have all been affected as the fallout continues. Follow the latest here.