The arrow!! I remember as a kid growing up in the Zone my Dad used to take us to areas where we could watch the Locks in motion.  One of my favorite things even years after was parking near the Locks and watching the approach arrow drop to show an approaching vessel as to what chamber they were to enter.  

This image is a very early "linen" post card of the North end of Gatun Locks.  This arrow is telling the approaching ship that they are to go into the East chamber. This was early visual technology at it's best and is still used today!!!  

This area of the Center Wall is also known as the "Turn Table" as this is where the Locks Locomotives prepare for the opposite direction transit after completion of another. 

Note the wonderful original cement lamp posts with the famous 400 pound cement decorative ball on top.  These balls were put all over the Canal Zone when these most majestic lamp posts were removed.  When the Aircraft Carrier "Essex" tried to transit the Locks, these lamp post became problems.  The "Essex" actually mowed down  a few.

I am planning another "Photo of the Week" in the near future in regards to the lamp post problems with BIG boats...  Although the original engineers of the construction days took in consideration lock chamber width, the didn't foresee that those very solid lamp posts would be a problem!

Another part of our Canal Zone history re-lived!  Long live the memories of our home!