With its mown lawns, neat red tiled houses and pristine avenues, the suburbs surrounding the Panama Canal look like a piece of Middle America from the 1940s or 1950s. But the calm image hides a transformation. Many – if not most – of the Americans who lived in the “Zone” have gone back to the US.

The government’s Panama Canal Authority now runs the canal and the military-run commissaries (grocery stores), schools and hospitals of the Panama Canal Company have long since been disbanded or transferred to local hands. The canal is slowly becoming integrated with the economy, its growth providing ever larger quantities of public revenues, with income from transit tolls and dividends up by more than five times since 1999, rising to $569.7m last year.