All the time you’re scanning the canopy for colourful birds, you are also keeping half an eye on ships in front and behind, both coming and going. This is another surreal aspect of the passage: 40 ships pass through every day, or 15,000 a year, day and night, so it’s really, really busy (at the mouths there are always dozens of ships waiting to enter) – and yet it is tranquil and, at times, weirdly quiet. The whole operation has a machine-like quality, well oiled after all these years.

If it’s a world wonder today, imagine what the Panama Canal was for those who first used it. When it officially opened on August 15 1914, the canal shaved weeks off the journey from the Atlantic to the Pacific. For example, the voyage from New York to San Francisco was reduced by 8,000 miles. Today, it takes a ship about nine hours to traverse the canal, or 22 days to get from Panama’s Caribbean coast to its Pacific coast via the Strait of Magellan – that’s 22 days, which is a long wait for bananas or frozen goods, and a lot of fuel. The weather down at Cape Horn is not so balmy, either.

Approaching Panama City – a headily glamorous and corrupt metropolis – lines of cranes and great mountains of shipping containers come into view. Merchant crews from all over the world are busy doing their jobs, but when you pass them close up on deck, you can see even they are excited to be using the iconic channel. As a proud Lancastrian, I see it as a descendant of the great Sankey Canal that first showed the world how to revolutionise transport with a spade and a pick and raw muscle. 

But the Panama Canal is more than that. An industrial landmark of the highest order, a conduit of global trade and a wildlife corridor of supreme importance, it ticks all the boxes for a traveller like me, equally enthralled by manmade ingenuity and nature’s gifts. So, here’s a feliz aniversário to Panama on its independence bicentennial, and a rum-cocktail cheers to another 100 years of Panama Canal cruising and conservation.

How to do it

Audley Travel (01993 838675; audleytravel.com) offers a 14-day Grand Tour of Panama package from £6,650 per person, including domestic and international flights, transfers, excursions and accommodation, as well as a partial transit of the Panama Canal. For recommendations on where to stay, see Telegraph Travel’s guide to the best hotels in Panama.