It went down smoking.

A last puff of smoke escaped from the top of St. Paul's former tallest building, the 570-foot-high smokestack at the High Bridge power plant, as it came down at 7:30 Saturday morning in a bone-shaking crash, felled by 202 pounds of explosives.

Its stately demise rattled windows, set off car alarms, sent a cloud of dust down the Mississippi River valley and thrilled thousands of early-rising onlookers who couldn't stay away.

Taller by almost 100 feet than the city's next surviving edifice, the 472-foot Wells Fargo Place, the smokestack, built in 1972, was a drab, gray, concrete poke in the sky that looked like something from East Berlin, circa 1960, and was considered an eyesore by many. But as homely as it was, the old stack was loved by many people on the West End and the West Side of St. Paul, which it stood between. It was a marker for their place in the world.

"That stack is our beacon," said Dayna Gay. "Whenever you saw it, it meant you were close to home."

Gay was one of a group of Michigan Avenue neighbors -- Jungbauers, O'Briens, Hortons and more -- who rolled out of bed at 6 a.m. for waffles and mimosas, served in a side yard, to toast the smokestack's last dawn. "We're honoring the stack," said Jim O'Brien, waiting for waffles. "I think we're all going to miss it."

O'Brien, a 46-year-old teacher and an artist, somehow found dignity in the gray tower of concrete.

"It kind of grew on me," said O'Brien, one of the many free spirits living among the little old houses between West 7th and the High Bridge, one of the oldest parts of St. Paul. "It's an interesting building that reflected the sun. And when it rained, you could see which way the wind was blowing by looking to see which side of the stack was wet."

"It was always our weather vane," agreed Dave Christofferson," 61, a longtime resident.

It served as a weather vane for the last time Saturday. The rising sun glinted off the downstream side of the stack as the crowd arrived. By the time everyone seemed in place, the skies clouded up and gentle raindrops began to fall as demolition time ticked down.

In its final act, the stack wouldn't just show which way the wind was blowing. It would show how the times are changing: The demolition came as part of a $380 million conversion from coal to natural gas by Xcel Energy at the High Bridge location, where the first plant started producing electricity in 1923. The old plant will be razed and the 50-acre site restored over the next two years, with the city eventually likely to wind up with a 20- to 40-acre new park on the river.

The new plant, already online, has twice the capacity of the old one and with far less emissions of gases such as sulfur dioxide and nitrogen oxide. Not to mention the dust that used to blow through the neighborhood from the now-vanished mountains of coal that used to stand above the river. The dust cloud that followed the 16-second thunderous collapse of the smokestack Saturday and rose above the High Bridge was the last one.

For those, like me, who grew up along the riverfront when it was the industrial heart of the city, the change has been huge.

Gone are the tank farms, the mountains of coal, the scrap yards, the can factories, the Schmidt brewery and, further downriver, the slaughter houses and cattle yards. "That's the smell of money," people would say whenever a kid complained about one odor or another as it wafted over us.

The money smell is gone. But the river valley -- the view of the wooded slopes of the West Side already vastly improved -- is more alluring.

"The river valley was desolate when I came here," said Bobby Kasper, a union official and transplanted New Yorker who loves his adopted St. Paul. "Industry filled the valley. Now it's being rejuvenated."

Kasper was bragging that it was members of his union, Laborers Local No. 132, who drilled the 404 holes at the base of the smokestack where the 202 pounds of explosive was planted. The charges were detonated over a half-second's time, blowing off five concrete supports for the stack, laying it down in the dirt to the west. Even though the stack appeared to fall slightly off target, barely clipping the ends of the piles of sand that had been laid out to cushion the fall, Kasper surveyed the new, less impeded view of the valley and proclaimed it good.

"The whole scenery of St. Paul is getting beautified," he said in his New Yawk accent as he pointed toward the high-tech electricity plant. "Just look at that new plant. I'm telling you, it's soft on the eyes. "

Still, there were wet eyes. A high school girl I know was sobbing as the stack came down, text messaging her friends about how sad it all was. I'm telling you, it had to be a big day, to get teens out of bed on a Saturday before noon.

Thousands of people lined the upstream side of the High Bridge and took vantage points all over the city -- some a mile away -- to see the implosion. But the crowd was quiet, almost somber, as the countdown proceeded. It was as if they were paying their last respects.

"It has a strange feeling, almost like waiting to watch an execution," said Sean Kershaw, the president of the Citizens League, who lives along W. 7th Street, and -- like many others on hand -- had dragged his drowsy kids to see history unmade. "That's one of the things I love about West Seventh," Kershaw said. "Where else would people romanticize a smokestack?"

St. Paul has always loved a good demolition. It's the city, after all, that gave us humorist Max Shulman and his creation, Dobie Gillis, who was often invited by his friend Maynard G. Krebs to "Go downtown and watch them tear down the Endicott Building."

Thankfully, Cass Gilbert's lovely old Endicott, 119 years old and on the National Register, still stands.

The Xcel Energy smokestack does not.

The takedown went off precisely on time. Unlike the 1985 demolition of the old High Bridge, which hung fire for hours and disappointed many who gave up and went home, this was a demolition derby for the people. The charges went off with a rat-a-tat-tat firecracker sound at the bottom of the stack, which wavered slightly, then sagged and began a regal demise, falling in slow motion, a heavyweight who could no longer stand. It was sad and awesome at the same time, like seeing the sinking of an ocean liner from a lifeboat, amazing that it could happen, such a huge thing going down. Tipping, turning, leaning, falling -- 16 long seconds before that last gasp of smoke escaped from the dying stack just as it hit the ground and collapsed onto itself in a thunderous clap of concrete and compressed air.

The river valley shook, the car alarms sounded, the people cheered. Some screamed, petrified for a split second, worried that the stack might somehow twist and lash out against the crowd.

"It felt like an earthquake," said Maggie Miller, whose windows, in the house next to the neighborhood wafflefest, shook in their frames.

Well, maybe it was an earthquake.

The ground has shifted.

"That was fun," Christofferson said. "We ought to do this every week." • 612-673-4400