Nature is a matchless architect but often a lousy storyteller. The story is there: It's in the fallen tree, the stalking fox, the beach-strewn conch. But nature doesn't speak our language, and we rarely take the time - or have the ability - to listen and translate.

At Natural Tunnel State Park in southwestern Virginia, nature's architectural handiwork is told in rock and water. And what a story it is.

The famous statesman William Jennings Bryan once called Natural Tunnel the "Eighth Wonder of the World." Had it been more accessible when the list was compiled, the tunnel might have made the original seven. It burrows through 850 feet of limestone and dolomite and is high enough inside for trains to pass through, carrying coal in all directions.

After the initial "wow" a first-sighting elicits, the next question is invariably, "How was that formed?" That's where a translator comes in, unless you're a geologist and speak rock and water.

Tony Scales is not only a geologist fluent in those tongues, he wrote the book on the place - "Natural Tunnel: Nature's Marvel in Stone." Scales, who lives in nearby Big Stone Gap, has been volunteering at the park since 1981. There is likely no better interpreter of nature's local architecture. I found that out first hand when Scales met me earlier this week for a park tour.

He started - as all tours here should - by educating me on the park's defining feature. Here's the thumbnail version:

More than a million years ago, water bearing naturally occurring carbonic acid trickled through the easily erodable limestone and dolomite bedrock. Deep underground, it found the Glenita Fault, where the rock was heavily fractured. This zone of fractured rock along the fault was even more easily eroded than the surrounding bedrock. What is now Stock Creek formed underground along the fault. Eventually, enormous sinkholes opened on each side of Purchase Ridge, which forms the roof of the tunnel. When the sinkholes eroded down to the underground level of Stock Creek, a tunnel was born. This all took more than a million years, a pittance in geologic time.

Confused? You won't be if you learn the history while staring at the tunnel itself. And it helps when your tour guide has written the book on what you're seeing. If that's not an option, the visitor center explains it all with pictures and models.

From the boardwalk at the south end of the tunnel, visitors can see the Glenita Fault and watch Stock Creek pass through the chasm alongside the Norfolk Southern rail line. One thing you won't see is out the other side: Stock Creek makes an S-curve inside the tunnel

Even in a park with a singular claim to fame, there is more to do than look into the geologic past. Scales and Park Manager Craig Seaver took me to all four corners of the park's nearly 1,000 acres. There are camping facilities (soon to be expanded), an amphitheater, a swimming pool and a few hiking trails, most of which traverse different sections of Purchase Ridge. The park lies along Daniel Boone's Wilderness Road, and boasts a replica of a 1770s fort - the Blockhouse - where historical reenactments take place.

Natural Tunnel State Park is very much a part of the local community, with seasonal festivals and music shows dotting the calendar.

"That's something we work very hard at," said Seaver, pointing out the different park features built by local volunteer groups. "It's a small-town area. In the late 1770s, they had to pool all the resources they had to make it and survive. The same thing is going on today."

The park also offers an impressive array of activities for adults and children both within park boundaries and in the surrounding wilderness. Chief interpretive ranger Megan Krager ticked off a partial list: caving expeditions, canoeing on the nearby Clinch River, summer camps for kids, hayrides and night hikes.

They also offer a guided hike into the tunnel via Stock Creek where it enters on the north side. There was no hike the day I visited, but Scales and Krager gave me the go-ahead to explore on my own.

I hiked down Spring Hollow Trail a half-mile to the tunnel entrance. The creek, which offers seasonal trout fishing, was low from lack of rain. I hopped from one limestone boulder to the next, passing deeper into the darkness with each step. I quickly came to the S-curve in the middle of the tunnel where the creek had worn a deeper pool. I saw the light at the far end, but not the outside. I was alone.

After spending the day with Scales, I could get a sense of this place thousands of years ago. The vaulted limestone ceilings were part of a cave then. Geologic forces - erosion, dissolution - were as relentless then as they are now. At some point in recent ancient history, light broke through, first on one side, then the other. The cave became a tunnel, and one of nature's grandest feats of architecture was exposed.