Cuba's government said late on Saturday it had restored power to nearly one-fifth of the island's people after the national grid collapsed twice in 24 hours, plunging millions of people into darkness. The unprecedented nationwide blackout is the latest blow in the nation of 10 million, already suffering from dramatic shortages of food, medicine and fuel. Cuba's top electricity official, Lazaro Guerra, said the grid operator was working to restore electricity but that the process would be slow and rushing the job could lead to more blackouts and a deterioration of service. "I cannot assure you that we will be...