It may not be as revolutionary as the Boston Tea Party or Paul Revere's midnight ride, but when two major sections of Boston's Big Dig - a highway tunnel sunk 120 feet deep and a soaring spider-web bridge - open to traffic on Sunday, it will mark the realization of a big idea: that cars should be banished from city streets, and pedestrians should reign.
To achieve this lofty aim in America's oldest major city has meant burying nearly four miles of highway, to create 44 acres of green space in the heart of downtown.
"We're throwing the autos out and making it more friendly for the people. We're sidelining cars and elevating people. We're putting cars underground and bringing people to the top," declares William Fowler, head of The Massachusetts Historical Society, who has clearly caught the vision.
Other cities have, too, albeit to varying degrees. From Milwaukee to San Francisco, looming highways are out; tree-lined boulevards are in. In a serious case of Big Dig envy, Seattle is hoping to replace its elevated highways with tunnels. Even London is trying to limit car congestion by charging downtown drivers at peak hours.
But nowhere is the attempt to bury the automobile and elevate the pedestrian more ambitious - and costly - than in Boston. The Big Dig is famously over budget. Estimated at $2.5 billion in 1987, it is now expected to cost $14.6 billion, most of which has come from Washington.
Former President Ronald Reagan, who fought the project, once said: "I haven't seen this much lard since I handed out blue ribbons at the Iowa State Fair." But House Speaker and Tip O'Neill, who represented Boston, led Congress to override Reagan's 1987 veto. The Big Dig was born.
In fact, says Mr. Fowler, the project symbolizes how skilled Bostonians are at staging revolutions. In Revere's day, he says, "Boston was the hotbed of the Revolution because we had a surplus of clever politicians." After the Yankee army formed at nearby Lexington and Concord, state politicos went to Philadelphia and convinced the other 12 colonies to fund new troops. Then, as now, he says, "We got the rest of the country to adopt our revolution - and got them to pay for it!"
But not everyone is pleased. "It's like we've built the pyramids 120 feet down in the muck of Boston Harbor - and pillaged the nation's highway funds to pay for it," says former newspaper columnist David Nyhan. He wishes the money had been spent on light rail or other mass transit, instead of enabling cars to remain the chief transport option.
Now Gov. Mitt Romney (R) and others are trying to recoup some of the billions spent on the project. A recent Boston Globe probe attributed $1.1 billion in cost overruns to mistakes by the Dig's management firm, Bechtel/Parsons Brinckerhoff. But most agree that the Dig is an engineering marvel - testament to the power of a simple idea to push the laws of physics.
Starting Sunday, when motorists drive north on Interstate 93 into Boston, they'll first be on a skyway above the city; then swoop down in a tunnel that runs beneath a subway line; then skyrocket back up onto the Zakim bridge to cross the Charles River. The Zakim is the world's widest cable-stayed bridge with 10 traffic lanes.
The project is an extension of Boston itself - a highly engineered city in which 70 percent of land is man-made. Many buildings float, Venice-like, on pilings. It's as if residents took God's command - "Let the dry land appear" - as their mission statement. Now, "Let the green space appear." And behold: It is almost done.
The greenway will emerge by 2005. One plan calls for a canal and promenade - with summer boating and winter skating. Another envisions elevated plazas and bridges looking out over the city.
No decision has been made. But pedestrians will rule. And will the revolution continue to spread? "Will funding for the Big Dig be replicated? Probably not," says Brookings Institution urban expert Bruce Katz, laughing. "But the bigger theory will be widely applied."