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

MADRID (AP) — The cause of Spain and Portugal’s widespread blackouts remained a mystery on Tuesday, with some isolated disruption remaining after power was largely restored to both countries.

Electricity was back in most of the two countries almost 18 hours after a blackout that shut down much of daily life. The cause of the outage remained unclear.

Play at the Madrid Open tennis tournament has been suspended because of a major power outage reported in Spain and Portugal.

Jacob Fearnley was forced off court after play was suspended at the Madrid Open due to the widespread power outage affecting Spain and Portugal.

Britain’s Jacob Fearnley was forced off court as play was suspended at the Madrid Open due to a power outage. The third-round tie between Fearnley and Grigor Dimitrov had reached a critical stage, Fearnley breaking the 15th seed’s serve to stay in the match,