While in Colon, Panama, some participants visited Gatun Lock, the largest and most comprehensive of the Panama Canal locks.
Walking up to the Gatun Lock visitor center. On the right are two versions of the pilot vehicles that pull ships through the canal. The black car, on the left, was the first. Next to it is the second version. Today a third generation vehicle is in use.
Part of the wonder of the Panama Canal is the mystery of how it works. Water enters and exits the chambers unnoticeably, filling and draining from below the ships. The only indication the lock is operating is a rising bubble of water around the vessel and the surprise when, after a few minutes passes, that instead of looking around at trees, the line of sight has dropped over ten feet to a view of a solid cement wall. In addition, no pumps are used to fill and drain the chambers, gravity does all of the work.
Two Panamax vessels (the maximum size ship that can fit through the canal) crossing simultaneously. Many ships are built to this specification for the express purpose of transiting the canal. These vessels are carrying large cargo containers. The gates of the canal are the same that have been used since the canal was completed in 1913.