Panama's new metro is seen from a house in Panama City April 10, 2014. The metro, a 13.7 kilometer line that also cost $2 billion, began service last week, becoming Central America's first subway. Panama will build a second subway line, with a tender expected before the end of April for construction of the project costing up to $2 billion, the head of the subway said on Wednesday. REUTERS/ Carlos Jasso (PANAMA - Tags: BUSINESS TRANSPORT)