MADRID/LISBON (Reuters) -Power started returning to parts of the Iberian peninsula late on Monday after a huge outage brought parts of Spain and Portugal to a standstill, grounding planes, halting public transport,

Officials are yet to confirm exactly what caused more than 50 million people to lose power this afternoon, with a number of potential explanations having been offered in the panic

Major power outages across large areas of Spain and Portugal, as well as parts of southern France, knocked out traffic lights and disrupted public transportation and airport operations on Monday. Officials did not say what caused the outages, but several denied any foul play.