Transit day!  We got up on the top deck in time to see the approach to the first lock.   We would be transiting the passage with the Norwegian Pearl, seen here on the left entering the first lock.   

The Pearl has only 2 foot clearance on each side within the lock.  

The ship ahead of us has exited, the gates are about to open to let us in, and then will close behind us and fill to bring the ship up to the level of Lake Gatun.   Here's the view behind us to as we exit the first lock.

And then we enter Lake Gatun, where we travel at a very leisurely pace.  It will take 9 hours to travel the 50 miles cut across the continent. 

And it is hot.   And humid.  Very uncomfortable and for the first couple of hours, I would go back into air conditioned comfort every 10-15 minutes to cool off.  About 11 AM, we found a corner of the ship with a breeze and shade and soon were treated to a tropical downpour that substantially lowered the temperature and humidity.  

One of the biggest obstacles in the completion of the Canal is the Culebra Cut,  the artificial path cut across the Continental Divide.

You can't pass through this engineering marvel without acknowledging and honoring the tens of thousands who died constructing the Canal.   I was chatting with another passenger who said the transit  was especially meaningful to her because it was a chance to experience history, not just looking at  another historical point of interest.  We were able to see the marvel in action: the locks moving, the continuing dredging, the evidence of the prior engineering innovations.