Today is the day. This is the reason why we are here on this cruise—we and about 2,500 other people. Fellow passengers who have been on this cruise before warn us: claim a good position, claim it early, and hold your own against the press of late arrivers. Some people, they tell us, actually sleep out overnight in the position of their choice.

Naturally, we want to know, based on their experience: what is the best position on the boat from which to view the transit? Suddenly, we have become potential competitors, and they are reluctant to say. Forward on Deck 6, maybe. Or Deck 11 or 12. Or along the side of the boat or aft on Deck 5.

We claim a position looking forward but along the side of the ship inside the Solarium on Deck 11. It’s not a recommended spot, but the mothers will be able to sit in comfort and to see.

This doesn’t last. We are too restless.

I find I can “Excuse me” through the crowds anywhere, anytime, as long as it’s just to take a picture and not to squeeze people out of their closely-guarded premier locations.

Like the title of this post, the Panama Canal itself is a palindrome of sorts. Ignore the punctuation, and you have three lock-chambers going up and three lock-chambers going down. But the punctuation gives it meaning: one lock of three chambers, a wildly free-form lake, a narrow channel dredged right across the continental divide, a bridge, a lock of one chamber, a smaller lake, a lock of two chambers, and a bridge.

There are two parallel passages through the locks, but only one-way traffic is allowed. We are assigned the port passage, behind the freighter Freja Breeze. Alongside and slightly ahead of us, the container ship Zim Haifa is making the transit. Zim Haifa is about as big as we are. We are both “Panamax” ships: the largest ship that can transit the canal. Construction now under way to enlarge the canal’s capacity will be completed on the canal’s centennial, in 2014.

Transiting the three chambers of the Gatun Locks takes most of the morning.

We burst into the glorious Gatun Lake shortly before lunch. Our 13-story oceangoing cruise vessel is now cruising an inland fresh-water lake some 85 feet above sea level.

I watch the passage of the strikingly narrow and long Culebra Cut, which includes one of only two bridges over the Canal, from a treadmill in the bow of the gym on Deck 12. The channel in the Cut is so narrow that two Panamax ships cannot pass; hence the need for one-way traffic.

By mid-afternoon, I have ensconced myself at the rail on Deck 6, one of those hotly contested premier positions earlier in the day and still crowded—but accessible. From here, my elbow-to-elbow neighbors—now my very good new friends—and I watch the transit of two more locks (Pedro Miguel and Miraflores) comprising three chambers in all. “This is a much friendlier crowd than up on Deck 11,” my neighbor to the left remarks. Maybe, I think, they’re friendlier up there too, now that we’ve been watching this canal for hours. “Oh yes,” says my neighbor to the right, “we’re not like them; we’re always willing to squeeze one more in.”

In addition to the impressive locks, we see strange and familiar birds, ice rainbows in the clouds, thunder and lightning, canal dredging and construction equipment, Miraflores Lake, and the Miraflores Visitors Center, a five-story building filled with tourists who are cheering us as we pass.

As the sun sets, we exit the last chamber and ride beneath the second of the two bridges and into the Pacific.