They used to use actual mules to pull the ships thru the canal. This is what a mule looks like in 2009.
This was in the morning, going from ocean to the lake between the two shores.
This is the afternoon, coming out of the lake and back in to the ocean (same side as we went in). You can see the local traffic going over the canal.
And lastly the bridge for the cars is stowing itself away before the last lock (before the ocean) is opened up for the ship.
This was truely a great trip!