A canal from the Atlantic to the Pacific and a highway from Alaska to Patagonia. Those were the two great infrastructure projects intended to transform the geography of the Americas. The fate of both schemes was determined in Panama. One eventually succeeded; the other failed.

Sitting in a boat on Lake Gatún, I am witnessing the successful scheme firsthand. To one side of us, a huge Japanese container ship inches its way along the 48-mile route of the Panama Canal, crossing from coast to coast, and in the process bypassing a 7,900- mile voyage around Cape Horn. This is proof, it would seem, of man’s triumph over nature.

But what of the other project? The Pan-American Highway effectively begins at Prudhoe Bay, on the shores of the Arctic Ocean. It meanders down through Alaska, Canada, the United States, Mexico and Central America, and crosses the Canal close to Panama City.

A white-faced capuchin monkey in Panama’s rainforest © Edurivero I Dreamstime.com

From there, the road curves its way along the spine of Panama until, at the town of Yaviza in the province of Darién, it stops abruptly. Any motorist with ambitions to drive the length of the Americas is thwarted by the 54-mile Darién Gap, an impenetrable swath of mountainous rainforest and swampland on Panama’s border with Colombia.

I gained some sense of the challenges that defeated the road engineers one morning when an intrepid Spaniard, Iñaki, drove me out of Panama City.

“Sure, I’ve been to Darién,” he said, as we passed the signposts counting down the mileage to the highway’s end. “Amazing. It is the last true wilderness in Panama, perhaps the world. It is tough but wonderful.”

After an hour, we turned off the highway onto a dirt track fringed by thickening forest. “From here it is 10 miles to my place. The first five miles …” He made a so-so gesture with his hand. “The last five miles …” He whistled and shook his head. “Every part of my Land Cruiser has been broken by this road. I have become an expert mechanic.”

The last section of our journey was every bit as difficult as he had indicated. At times, the road disappeared completely; Iñaki steered an impromptu route across recent landslides. The vehicle slithered across loose earth and jolted each time it struck concealed rocks or boulders.

At last we reached a meticulously maintained driveway and drove up to a line of simple thatched huts occupying a grassy ridge. “Welcome,” Iñaki said. “This is my place, Burbayar Lodge.”

We got out. I turned to compliment Iñaki on the stunning setting, but he had vanished. For an unnerving moment, I felt completely abandoned on this cleared ridge in the foothills of the San Blas Mountains.

“Iñaki?” I said, trying to disguise my anxiousness.

“Si.” His voice came from under the vehicle. He was checking the damage caused by our journey.

Then he gave me a tour of the property, introducing me to the motley collection of residents: cats called Carrot and Livingstone, a dog called Sophia, a parrot called Socrates and a hand-reared red brocket deer called Mandarina. I also met two members of the staff, both local Kuna Indians: Christina, the cook, and Fernandez, the handyman.

Iñaki and Fernandez took me on a hike through the surrounding forest after lunch. Iñaki told me that because of the state of the road, the Kuna Indians were effectively cut off from the rest of Panama. “They are in two minds about improving the road. At the moment, they are protected by isolation. It is good for their culture, but it also makes life very hard for them. For me also.”

We walked along muddy animal trails. Fernandez identified animal spoor, and Iñaki interpreted: “This print is an ocelot. This one is a tapir. Here, a puma.”

Within the dappled, colonnaded vault of the forest, the greater geography was obscured. Iñaki gave me the bigger picture: “This way is north, seven miles to the Caribbean Sea — but from here to there, big mountains. East, the forest goes to Darién. West, it stops at the Canal. South, where we came from today, it is 30 miles to the Pacific. We are in the middle of …”

“Of nowhere,” I said. Iñaki nodded with calm contentment.

Night fell quickly after our return to the lodge. There was no electricity, only dim solar-powered lamps to see by and a fire to cook by. I wandered outside and was instantly enveloped by inky blackness. The stars shimmered overhead with incredible clarity. Primeval sounds reverberated in the jungle valley. I slept in a hammock on the veranda.

All too soon, I had to return to Panama City. Iñaki drove me back. Part of me hoped that the road would thwart us and that I would be forced to stay for a day or two longer. But he was expert at negotiating the approximation of the road, and after an hour we turned onto the smooth asphalt of the Pan-American Highway.

As he left me at my downtown hotel, I asked what burbayar meant.

“It is a Kuna word,” he said. “It means — how you say? — ‘spirit of the mountain.’”

Contemplated from among the capital’s hectic jumble of highrises, that spirit seemed very distant and very fragile. I stayed in the city for a couple of nights before transferring to Gamboa Rainforest Resort, which was the absolute antithesis of Iñaki’s rustic retreat.

The resort, which had something of a Jurassic Park ambience, was set within sculptured grounds, with the natural chaos of the forest carefully kept at bay. From here, I was just a short distance from the Canal and the legendary Pipeline Road, one of the greatest bird-watching venues on the planet (it was on this unassuming service road through the forest that 367 bird species were recorded in a single day — the world record).

One day, a few years before, I had joined primatologist Dennis Rasmussen for a boat trip on the manmade Lake Gatún, created in 1914 when a valley was flooded to form the broadest section of the Panama Canal.

“The hilltops became islands,” Dennis told me. These isolated fragments of forest — the Tiger Islands — had become a monkey sanctuary to which he and his researchers reintroduced tamarins, capuchins, howler monkeys and spider monkeys. The clearest view of the primates was from the water, and so we navigated around each of the islands while the big ships filed past in relentless procession.

Suddenly the boat slewed sharply to one side, then stopped. Dennis cut the engine. “Guess what? We’re stuck up a tree.” Sure enough, as I looked over the side I could see beneath the surface the tangled upper branches of a near-century-old tree that had been swallowed up in the manmade flood. Now, as if to have the last laugh, it had us firmly in its clutches. We labored for 10 minutes with oars and the outboard to free our craft.

The Panama Canal © Adeliepenguin I Dreamstime.com

The Panama Canal is currently undergoing a $5.5 billion expansion program that, by 2014, will allow much larger ships to navigate across the Central American isthmus. Construction cranes loom over the giant new locks. Existing channels are being widened; new channels are being excavated. It appears man’s dominance over nature is being reaffirmed in spectacular fashion.

But then I think about the Pan-American Highway, defeated by the wilds of Darién. I think about the untouched forest around Burbayar Lodge. And I recall the minutes I spent stuck in a treetop in a boat. For all our pretentions, nature’s majesty and power can still leave us humbled. Nowhere is that better illustrated than in Panama.

Panama Info to Go

Tocumen International Airport (PTY), 15 miles east of Panama City, is served by direct flights from several U.S. cities. Accommodation at Burbayar Lodge costs $190 per person for one night and $155 per person for each subsequent night. Rates include transfers from/to Panama City, one guided hike per day and all meals; a visit to a Kuna Indian village can be arranged. Rates at Gamboa Rainforest Resort start from $135 per person. Excursions to the Pipeline Road and to an island on Lake Gatún can be booked at the resort. The truly adventurous can book tours to the formidable rainforest of Darién Province at www.traveldarienpanama.com; cost from $300 per person excludes transportation from Panama City.