PORTLAND — The Waldo-Hancock Bridge was an engineering marvel when it opened in 1931 with its soaring suspension cables and 206-foot towers rising out of the Penobscot River, a gateway to eastern Maine.

The aging bridge now stands neglected next to its replacement – the even bigger and more impressive Penobscot Narrows Bridge – with peeling paint, rusting steel and missing chunks of concrete that have fallen 135 feet into the river below. Six years after the bridge closed to traffic, work has now begun to demolish the historic structure. When the job’s complete next spring, virtually nothing of the old bridge will remain other than two concrete piers in the river.

The end of the bridge will mark the end of an era, said Dave Milan, the economic development director in Bucksport, who’s been viewing the bridge all his life. From his office window, he now has a view of the old bridge, in front of the new bridge that stands behind it and has been open since 2006.

“The bad news is we’re losing an iconic view,” Milan said. “The good news is we’re getting a better iconic view. Frankly, the old bridge blocks the new bridge.”

Workers began arriving this week, setting up staging areas and preparing the site for the nine-month project. The bridge crosses the Penobscot River and links the towns of Prospect and Verona Island, as well as Waldo and Hancock counties.

The bridge will be dismantled in reverse order of how it went up, said Doug Coombs, project manager for the Department of Transportation. Federal funding will pay for 80 percent of the $5.3 million price tag, with the state paying the rest.

Demolition crews will first remove the bridge deck in 25-foot sections, starting in the center and working toward each shore. The next thing to go will be the bridge cables, which will be cut from the center of the bridge and from anchors on both shores. The last things to come down will be the bridge towers, which will be cut into pieces with blowtorches.

All the material will be lowered by a crane onto a barge in the river, which will take the steel and concrete to shore, where most of it will be recycled.

When the bridge is dismantled, all that will remain are the concrete piers in the river that hold the towers in place. The piers, which rise 29 feet above the water and sink 45 feet below, will have blinking white navigational lights put on them to serve as warnings to boat traffic on the river.

A viewing area will be constructed on the Prospect end of the bridge, with old bridge plaques and informational panels about both the old and new bridges. The flag poles that now stand atop each tower will be given to the towns of Prospect and Verona Island as keepsakes, and sections of cable and other artifacts will go to those two towns and Bucksport.

By the end of June, the bridge is expected to be gone – and with it the end of a landmark that’s been a familiar sight for generations of Mainers and visitors traveling to eastern Maine.

When the bridge was built, it was named the nation’s most beautiful steel bridge in its class by the American Institute of Steel Construction. The bridge cables and towers make it look like a miniature Golden Gate Bridge, which opened six years later.

The bridge was a product of the emergence of automobile travel and the tourism trade in Maine, said state historian Earle Shettleworth Jr. No longer were travelers satisfied with the ferry that crossed the river from Prospect to Bucksport, he said.

Designed by noted bridge designer David Steinman, the bridge was a major engineering feat for both its aesthetics and for overcoming the challenge of crossing a difficult section of river, he said.

But the replacement Penobscot Narrows Bridge isn’t too shabby. An impressive cable-stay structure with two towers and a roadway held up by steel cables, it features a 420-foot glass-enclosed observation tower with commanding 360-degree views.

“The Waldo-Hancock Bridge is one of those landmarks in Maine that people have personal connections to in their lives,” Shettleworth said. “Yet we have a new landmark now.”

When Milan looks at the bridge, it brings back memories of when he was in high school and walked up one of the bridge’s cables to the top of the tower. It was a rite of passage for him and thousands of other teenagers over the decades.

He’s now thinking of asking the demolition crew if he can walk up one of the cables one last time before the bridge comes down – for old time’s sake.