When I arrived in Panama City airport, I saw lots of people but no signs for an immigration or arrivals. Almost like an afterthought.
Of course, I visited the canal. It’s a fairly easy 20 minute ride from Panama City. Some folks told me that it wasn’t worth it. I found it more entertaining than I expected. It took three hours to watch the film (an interesting version of history) which was fortunately short, and then to watch the huge container ship pass through the canal at some infinitesimally slow rate. I kept looking at the containers and imagined my worldly possessions passing through the canal while I watched from the side. For an hour.
During the passage, there were informational announcements including the nugget that it costs $350,000 (or more) in CASH per ship to pass through the canal!