The dark, in fact, is an important part of the experience, though the quality of that darkness has changed over time — but more on that later. For now, we’ve driven into the tunnel. That distinctive stone portal diminishes behind us, a glowing arch floating in blackness in the rearview mirror, and for a moment, we see no corresponding archway in the darkness ahead. The road nestles into the curve along the mountainside, and the tunnel curves with it, limiting our view. We were driving toward a mountain, and then we drove into a hole, the radio went silent, and then the lights went out.

If you don’t think that’s incredibly cool, ask your kids.

Then, a small opening appears, and grows, and our eyes adjust. Sunlight. Space. And, in front of our eyes, from nowhere, a vista of the Blue Ridge Parkway. Maybe there’s a mountain framed in the entrance; maybe we’re looking into a valley or a series of valleys. But everything has changed. We were someplace; now we’re someplace else. We were looking west; now we’re looking east. The tunnels on the Blue Ridge Parkway transport us. I mean this literally: We start in one place and end up someplace else.

If you think I’m overstating the experience of driving your car through one of the tunnels on the Blue Ridge Parkway, perhaps you’re right. But I didn’t come up with the notion.

“The phrase we use today,” says Gary Johnson, retired chief landscape architect for the parkway, “we talk about a cinematic experience.”

Exactly. Think of the beginning of a movie. You walk cautiously down a close, darkened aisle, with just enough light to navigate by. Then, just as you’re getting comfortable in the dark, here comes the movie, and some sudden vista of light and openness and delight flings itself at you, and you’re lost in an experience that a moment before you couldn’t have imagined.

Or think even of a specific movie — remember Dorothy, creeping forward to open that door that led from sepia-tone reality to Technicolor Munchkinland? If you remember to let the tunnels envelop you, however briefly, your emergence, time after time, can be just as thrilling.

“What are we going to see next?” Johnson says of the transitions the parkway tunnels provide. “It creates a lot of suspense.”

• • •

The suspense is by design. From the beginning, the Blue Ridge Parkway was more than just a way to get from here to there, and the tunnels, though placed and built by necessity, were a planned part of the driving experience the engineers and landscape architects created.

So says Ian Firth, and as the person who prepared the parkway’s National Landmark application about a decade ago, Firth ought to know. In recent decades people have shown special interest in the parkway’s social and environmental history, but Firth, professor emeritus at the University of Georgia College of Environment + Design, says, “I’m interested in the parkway as a great work of art. I would compare it to a Gothic cathedral.

“It’s got a story to tell, from a design point of view, and all parts of it, big and small, are related to some central theme.”

The parkway has had two themes from its earliest days as one of the first projects of the Public Works Administration created during the first hundred days of President Franklin Roosevelt’s New Deal.

“First,” says Firth, “what the designers were saying is the parkway is an ideal road for automobiles.”

That is, it wasn’t just a way to get from Great Smoky Mountains National Park to Shenandoah National Park. It was meant to be a delightful driving experience, designed for modern cars traveling at modern speeds.

Parkway planners have carefully chosen plantings along the road, with the road itself designed and placed so as to vary what travelers see, going from mountain to valley, from rock to creek, from farm to forest. Landscape architects and engineers staged the entire 469 miles of the Blue Ridge Parkway. It’s highly telling that the government reached out to a landscape architect — Stanley Abbott, who drew his inspiration from Frederick Law Olmsted — before getting the engineers involved.

That design and placement of the road was itself the second main theme of the parkway, Firth says. “The road was to belong — or to appear to belong — in the southern Appalachians, and not appear to be an intrusion.” Though people argued long and hard about whether the road belonged on the ridge, in the valleys, or all mixed up somehow, the principle of the road fitting its surroundings like it had grown there organically was part of its goal from the start. “It was very important to the landscape architects and engineers that when you came out the other side, you would be following the landscape,” Johnson says. “The curve in the road would make sense to you.”

Says Firth, “Everybody used the term for the road to ‘sit lightly upon the ground.’”

• • •

Now, you’re driving this beautiful road, and the whole idea of it is to feel like it belongs here, like it works perfectly for enjoying your drive. How does that lead to those stone portals, to the inky blackness of those tunnels, to that whole cinematic experience we’re talking about?

For one thing, the road fitting the landscape means it has to take sensible lines. Up north in Virginia — where there is exactly one parkway tunnel in the entire state — the Appalachians form an orderly ridge, marching northward in a straight line along which a road can gently curve and glide without too much creativity on the part of engineers.

Down here in North Carolina, though, we’re disorderly right down to our very geography. “We have that complex ridge system,” Firth says — with side ridges, intersecting ridges, and all kinds of other geologic complexity left over from the last time North America and Africa crashed into each other, which caused the Appalachians in the first place. And to run a road through that — particularly a road that nestles into the curves, that “sits lightly upon the ground,” you find that drilling tunnels causes less scarring than either winding way out and back along the perpendicular ridge or, worse, carving a deep cleft into the mountain.

Since you can’t circuit the ridge, and you don’t want the parkway to be a mountaintop-removal driving experience, that leaves tunnels. There are 26 of them total (25 are in North Carolina), and they range in length from 150 feet at Rough Ridge (mile marker 349) to 1,434 feet (Pine Mountain, mile 399.1).

Each tunnel has the same design: five-foot side walls to what Firth calls the “spring line” — the bottom of the arched roof and the part that makes the arch “spring” — and then a semicircular arch on top. Many were dug by drilling platforms called “Jumbo Rigs” — truck-mounted platforms decked out with water-cooled drills. They’d poke holes in the rock, then workers would place dynamite, and blam. They could advance about 10 feet a day.

And those distinctive stone portals? The beautiful arches surrounded by toothlike stones that make the tunnel entrance look like a giant’s mouth drawn by a child? Those are comparatively new, added in the 1950s and 1960s. They were not part of the original design.

• • •

The original plan called for the tunnel openings to be left — of course — natural, but once rain and the freeze-thaw cycle had their say, the parkway construction managers decided that preventing loosened rock from falling on people’s heads slightly outweighed sitting lightly on the ground. After World War II, parkway engineers and architects decided to steady the tunnels’ mouths by building portals. For that, they turned to the stonework that by then, courtesy of the national parks out west, had become all but shorthand for rustic architecture. It had already been used on many of the bridges along the parkway.

But — irony alert. That stonework screams “National Park,” and here it is shoring up tunnels on a parkway that was supposed to radiate a local sense of place. “But,” says Firth, “there was almost nobody around who could do that work.” We never built many cathedrals in the Appalachians, so the local tradition of stone engineering and masonry was lacking. Special stonemasons imported from Italy, Spain, and Brazil had to make tunnels through the southern Appalachians look like they belonged here.

• • •

Still, a good idea doesn’t die easily, and though the craftsmen weren’t from around here, other decisions helped the tunnels sink roots deep into the mountainsides. Each tunnel got the stone for its portal from quarries nearby — within around a dozen miles — so the stonework would fit with the rock laid bare by the road cuts themselves. And the attentive parkway driver can see it. “If you look at the structures around Grandfather Mountain,” Johnson says, “that stone has a kind of green hue to it.” Go north to Virginia, and the “stone used for curving and to finish bridges is actually a pink granite.” Though there’s more to it even than that. Johnson says he went to Virginia around six years ago to look at rock samples for a bridge, “and I saw these piles of pink rock and I said, ‘My gosh, where did we get that?’ We got that rock from the same quarry we got this section of the parkway from,” Johnson recalls. So time and weather change the rock more than just the erosion that necessitated using the rock in the first place.

And with all that old-world masonry, each bridge, of course, is different. Masons got basic guidance from the National Park System, and then they did their stuff, which you can see today. At the Little Pisgah Tunnel at mile marker 406.9, the portal stone stretches to the very mountain rock. Lichens, mosses, and water streaks embrace the rock, their pale and dark greens and white tracks enlivening the greys and browns of the stone itself. The Fork Mountain Tunnel at mile marker 404 has smaller stones that seem to accentuate its longer curve. The Little Switzerland Tunnel at mile marker 333.1 is so verdant it looks like it emerges from a green hillside, whereas the Craggy Pinnacle Tunnel at 364.4 has only the lightest stone trim around its mouth, with a vast rock overhang reminding you that for all the work of the engineers, most of the rock stays where it is because it’s part of a mountain and has been there for hundreds of millions of years.

• • •

By the way — if you’ve ever driven through two tunnels very close together, someone in the car has probably said, “Why didn’t they just connect them?” and sat there for a beat before everyone started laughing at the idea of building a tunnel where you didn’t have to dig one in the first place. But that almost could have happened on the parkway. The tunnel portals were extended in many cases as far as 10 or 15 feet from the tunnels’ ends, Johnson says, in case anything fell off from higher up the mountainside. You can find a good example of this at the Twin Tunnels (mile markers 344.5 and 344.7), where the inside of the tunnel retains its rocky texture but suddenly becomes smooth as you get to the portal extension. Even the closest of the tunnels — like, say, Ferrin Knob Tunnels 2 and 3, only a couple hundred feet apart — didn’t connect, of course, but the point is, what started out as natural holes blown in the rock ended up as remarkable building projects. Cathedrals, indeed.

• • •

Inside the tunnels, the tunnel lining has a story of its own. Mountains drip inside, not just on the surface, so the insides of the tunnels liked to fall down, too, and the tunnels commonly closed in the winter when that freeze-thaw cycle made things particularly avalanchey. And once the builders started using concrete lining, they noticed that it made the tunnels less foreboding. “From the experience of the tourist, the concrete is lighter” and reflects light better, Firth says. Before the lining, “those must have been some pretty dark holes.” On the Blue Ridge Parkway, even the quality of the darkness within the tunnels has been carefully crafted.

And if you’ve never noticed all those details before — well, that’s the point. “When people drive the parkway, they don’t observe a lot of the subtleties of the design of it,” Johnson says. “Because it’s so well done.”

It sits lightly upon the ground, just as it was supposed to. Now, keep driving until we hit another tunnel. Then — sssshhhhh.

The show’s about to start.