Two hundred years after they began dotting the countryside, the country's covered bridges have one plank in the past and one in the present. Beloved as picturesque throwbacks, many remain vital transportation links in rural communities from Vermont to Oregon.
Now, the Smithsonian Institution is celebrating them with a traveling exhibit that traces the history of an institution that holds a unique place in the hearts -- and communities -- of America.
"In the 21st century, we think of covered bridges as these quaint relics of the past," said Katherine Krile, project director for the Smithsonian's traveling exhibit series. "What they were, in their time, were remarkable achievements in civil engineering. They helped push forward the growth of the U.S. for over a century."
"Covered Bridges: Spanning the American Landscape" uses historic photographs, schematic drawings and other paraphernalia to bring the structures to life, showcasing not only their importance as river passages but also the appeal they continue to hold as cultural icons.
"We tend to take these structures for granted," said Coburn. "Many of us drive over them every day. But there's a lot of people that come to Vermont and New Hampshire to see covered bridges."
America didn't invent the covered bridge, it just helped perfect it.
Wooden bridges date to the time of Julius Caesar, who is said to have built a timber pile bridge over the Rhine River in 55 B.C.
Covered bridges evolved as a way of preventing bridge decks from rotting from exposure to the elements, the first American one being built over the Schuylkill River in Philadelphia in 1805. Soon, they began popping up everywhere, with bridge artisans improving on the engineering and aesthetics of the braces, posts and trusses that supported them. By 1870, there were an estimated 10,000.
They had their rules: Tolls were common, as were signs on either side warning horse drivers to slow down.
"One dollar fine to drive any team faster than a walk on this bridge," read the sign over a covered bridge built in Bath, N.H., in 1832.
Invincible they weren't. Prone to arson fires and vulnerable to floods, the bridges' usefulness faded with the development of more sophisticated techniques and the evolution of the automobile in the 20th century.
"A lot of [covered] highway bridges were built for loads of hay, so that when heavier and wider loads started coming, they had to rebuild," said David Wright, president of the National Society for the Preservation of Covered Bridges. "And when you rebuild, you rebuilt with contemporary materials."
As the bridges began disappearing in the mid-20th century, their cachet grew. Advertisers used covered bridge icons, paint companies marketed colors like "covered bridge red" and aficionados built replicas on golf courses and elsewhere.
Parke County, Ind., which bills itself as the covered bridge capital of the world, has about 30 of them and hosts an annual covered bridge festival each summer.
"Aesthetically, they pack a great punch," said Wright. "And they're useful structures, relatively easy to repair and unaffected by salt."
Today, about 750 remain, with the biggest concentration in Pennsylvania. Vermont has about 80, though not all are still in use. Among them: the Windsor-Cornish bridge, a 460-foot long span over the Connecticut River that links Vermont and New Hampshire, about 12 miles south of the Norwich museum where the exhibit is being staged.
Built in 1866, the bridge remains in operation, and continues to draw visitors. The warning sign -- "Walk Your Horses or Pay Two Dollars Fine" -- still adorns the entrance, even though traffic today is automotive.
Area's covered bridge a hot spot for visitors
Listen hard enough, and it's not too difficult to imagine the clip-clop of horses echoing off the wooden planks of the Bollinger Mill bridge.
It's been more than 30 years since the bridge ushered any cars over the Whitewater River in Burfordville, and even longer for horse-drawn buggies. But footsteps can still be heard inside the 140-foot-long span on a regular basis, in the form of visitors to the nearby Bollinger Mill.
The Cape Girardeau County bridge -- originally constructed in 1858 -- is the oldest of the four left standing in Missouri. Sandy Creek covered bridge in Jefferson County was built in 1872. Locust Creek bridge in Linn County was built in 1868. Union bridge in Monroe County was built in 1871.
The bridge is a Howe Truss construction, built by Joseph Lansman. The structure was destrotyed in the Civil War by Union soldiers, and rebuilt along with the grist mill after the war ended.
The bridge is 140 feet long, 12 feet wide and "a load of hay high", or 14 feet tall.
In 1961, the mill property was given to the Cape County Historical Society by the ancestors of George Frederick Bollinger, who built the mill in 1868.
With insufficient funding to restore the mill, the historical society deeded it to Cape Girardeau County, which in turn offered the property to the State Park Board. It's now under the oversight of the Missouri Department of Natural Resources.
From March through November, tours of the historic site are given on demand during the hours of 10 a.m. to 4 p.m. Monday through Saturday and 12 p.m. to 4 p.m. on Sunday.
From December through February, tours are given on demand during the hours of 10 a.m. to 4 p.m. Tuesday through Saturday.