I have done the full Panama Canal cruise a few times. The canal only allows the large ships through during the day, the nights are mostly small ships due to how tight it is to navigate through the canal. What this means is that on both sides of the canal, the Caribbean and the Pacific side at night it is a giant parking lot for ships. It is actually quite beautiful to see all the ships lit up at night with all the different size and configuration of shapes of different ships. I find it facinating to see and can sit there for hours watching all the lights.