MOUNT JEWETT, Pa. -- Even before its tattered remains were reimagined as a spectacular walkway over one of Pennsylvania's prettiest gorges, the Kinzua Viaduct was one for the history books.
When it rose some 300 feet above the ground more than a century ago, the structure was the largest and longest railroad bridge in the world -- higher even than the world-famous Brooklyn Bridge. Built of wrought iron by Civil War general-turned-railroad tycoon Thomas Kane, the engineering marvel stretched 2,053 feet across the Kinzua Valley, making it easier for workers to transport coal, oil and lumber across the region's rugged terrain.
Dubbed the "Eighth Wonder of the World" by its promoters, the bridge in 1900 was reconstructed to accommodate weightier, modern trains using 6 million-plus pounds of steel held together by 895,000 rivets, and for the next half century it reigned as McKean County's industrial workhorse. Even when it was pulled from commercial duty in the late 1950s because trains had become too heavy, it still saw heavy traffic -- from feet. Locals and tourists alike loved walking its wooden ties across the Kinzua Gorge (it's pronounced "Kin-ZOO," with a silent "a") and hiking the woods below.
In 1987, years after the state purchased the bridge and created a state park around it, its tracks once again rang with the clang of steel on steel. The main attraction of the tourist Knox & Kane Railroad through Allegheny National Forest was a scenic, bouncy ride over the gorge.
"Man, I used to walk across the bridge all the time as a kid," says Joel Broad of Butler, who on a recent, sunny Thursday was visiting the site. In September 2011 it was reborn as the Kinzua Sky Walk (kinzuaskywalk.com). "I remember when I was 7, I leaned over the side and thought I was going to die. But we still liked to fly foam planes off the center."
Those fun and games came to an abrupt end in 2002, when inspectors discovered extensive rust on the structure and shut it down for repairs that would never be completed. On July 21, 2003, a tornado with 100 mph winds and torrential downpours ripped through the valley, pulling hundreds of trees from their roots and tearing 11 of the bridge's 20 towers off their foundations. Within 30 seconds, the middle two-thirds of the bridge lay twisted on the ground.
When Mother Nature abruptly shuts one door, though, human ingenuity opens another.
The wreckage of the former bridge -- placed on the National Register of Historic Landmarks in 1977 -- still lies tangled in the grass on the gorge floor. Yet what managed not to fall is today even more awe-inspiring.
The nine remaining towers (six on the south end and three on the north) have been fashioned into a $4.3 million pedestrian walkway with a glass-bottomed observation deck that juts some 600 feet into the Kinzua Valley. It offers those who dare walk to the end spectacular views of the valley below.
If you're acrophobic, it can be a scary stroll in the sunshine, especially if you choose to walk on the spaced wooden ties of the railroad instead of the wooden deck that straddles it. But no worries: They're not wide enough to slip through and a chest-high rail the length of the walkway means you won't topple over, either.
"I was scared to death the first time I did it because I'm not a big heights fan," says Mr. Broad's girlfriend, Dayna Sikorski of Butler. "But once you get out there, it's really worth it."
Since its grand opening two years ago, the skywalk has quickly become one of the area's top tourist attractions, drawing more than 130,000 visitors each year. Hikers are officially prohibited from hiking down the hillside to the valley below, but not everyone follows the rules. Mr. Broad, for one, has made the half-hour climb numerous times in search of railroad spikes and lag bolts amid the wreckage.
"It's really kind of cool," he says. "It's only when you're at the bottom and look up that you can really see how big it is."
We opted to get a better view of the walkway from a small observation deck built into the hillside just off the parking lot.
With miles of hiking trails nestled under the shade of old-growth trees, much of it alongside bubbling brooks, Allegheny National Forest is gorgeous any time of year. But it's particularly lovely in fall, when the leaves on its many oak, maple and black cherry trees turn from candy yellow to candied-apple red, and roadside stands tempt with farm-fresh apples and bright-orange pumpkins. So fall is the perfect time to plan a visit to the Sky Walk, and then explore the small towns surrounding it.
This year, the colors in northern Pennsylvania are expected to peak in mid-October. For a weekly fall foliage report, visit www.leafpeepers.com/pa.htm or call the visitPA hotline at 1-800-847-4872.
Correction, posted Sept. 16, 2013: The location of Kinzua Sky Walk in Pennsylvania has been corrected.
Gretchen McKay: firstname.lastname@example.org, 412-263-1419 or on Twitter @gtmckay. First Published September 15, 2013 4:00 AM