It started over nothing - a police call about a maroon Buick blocking an intersection in North Philadelphia.

Frustrated drivers leaned on their horns as traffic backed up around 22d Street and Columbia Avenue.

When motorcycle officer Robert Wells arrived, he found Rush Bradford standing in the street, arguing through the driver's side window with his wife, Odessa Bradford.

She pressed one foot on the gas and the other on the brake, making the engine roar.

"Lady," the cop told her, "let the man park this car on the side."

She responded, "He ain't going to move a damn thing."

Wells told her to get out. She refused. He pulled her from the car. She punched and kicked him. He handcuffed her.

A crowd gathered.

A police wagon pulled up, and Officer John Hoff held the door as Wells put Bradford, still cursing and shouting, into the back.

People began yelling at the cops: Why were they mistreating a black woman? A man rushed up and slugged Hoff in the head, knocking him down.

A brick flew. Then a bottle.

Wells radioed "assist officer," a priority call that means an officer's life is in danger. More cops arrived, and rocks and debris rained from the rooftops.

It was 9:35 p.m. on a summer Friday, Aug. 28, 1964, and the Columbia Avenue riot had begun - an outbreak of violence and destruction that forever changed a neighborhood and a city.

When the chaos ended, three days later, hardly a store in the business district had its windows intact. And a lot more than glass had been broken.

For a large swath of North Philadelphia, the riot was what scientists call an extinction event.

Already teetering because of blight, government indifference, and massive white flight, the riot pushed the area over the edge.

Businesses fled. Property values sank. Even cabs stopped coming.

Today, 50 years later, the riot zone is at once desolate and prosperous, home to ruined storefronts and comfortable pubs, to abandoned buildings and new, lower-income housing.

Walk west from Broad Street on what is now Cecil B. Moore Avenue - renamed in 1987 to honor the civil-rights leader - and the street pulses: the shopping, business, and theater complex of Avenue North, a Temple University bookstore, university housing, Lee's Foodway, the Draught Horse Pub.

A torrent of new and renovated apartments has been driven by the demands of 13,000 students living on or near campus.

Some applaud the vibrancy. Others say catering to students is no way to rebuild a neighborhood.

Development is edging west, and it's easy to think it will eventually reach 22d and Columbia, the riot's epicenter. A new health center is being built on the southeast corner.

But the area has been blasted by population loss - a 65 percent decline between 1950 and 2010. Poverty is pervasive.

"There's hope, even though it's not what I would have hoped for," said Germaine Ingram, the acclaimed dancer, whose parents ran a real estate firm at Columbia and Bouvier. "The area is racially diverse now, what with so many Temple students living in the area. But I don't see much that suggests a sense of community there - certainly not for black people."

Today, many see the riot's angry echo in Ferguson, Mo., where hundreds of protesters have fought police over the shooting death of an unarmed black teenager.

"The same thing that happened years ago is happening today," said veteran Philadelphia civil-rights activist Karen Asper-Jordan. "You have police brutality, you have injustice. . . . Black children are not getting the support they need, and you wonder why people are so angry?"

On that long-ago Friday, the riot spread east to Broad, onto Ridge Avenue, and west to Fairmount Park. Random incidents occurred across North Philadelphia.

More than 600 businesses across 300 square blocks were damaged or looted, at a cost estimated at $4.1 million - worth $35.1 million today. About 340 people were injured, including 100 police officers. One person was killed: Robert Green, 21, shot by police who said he came at them with a knife.

At one point, the city deployed 1,800 officers - many of whom slipped off their badges to avoid identification.

"They whipped everything that was running - women, babies," said Bill James, 73, a longtime neighborhood resident.

"You would have thought it was down South," added Charles Gadson Jr., 63. "There were hard feelings toward the police."

Within minutes of Officer Wells' emergency call, about two dozen cops arrived at 22d and Columbia. It seemed like the incident was over.

But a block away, a man began shouting that white cops had beaten a pregnant black woman to death. The rumor spread.

By 11 p.m., the streets were filled with milling crowds and anxious cops. A patrol car turned onto Columbia at 20th - met by a barrage of stones.

The crowds began smashing store windows, carrying off dresses, groceries, cigarettes, and shoes. Some people used shopping carts to ferry their haul. Fires burned in cars.

Most avenue businesses were run by white, Jewish owners, the customers almost all black. Some black merchants managed to rush to the scene and save their shops by placing signs that said, "This is a Negro store." A Chinese restaurant owner posted, "We are colored too."

Police established a command post. But instead of pummeling the rioters, Police Commissioner Howard Leary held back, ordering officers to contain the violence and calling on black leaders to help end the disturbance.

That infuriated Deputy Commissioner Frank Rizzo, who wanted to stop the riot with a full frontal assault - and later called Leary a "gutless bastard."

WDAS disc jockey Georgie Woods drove through the neighborhood, his car loudspeaker blaring, "Please get off the streets. If you have problems, this is no way to solve them."

He was ignored.

A crowd jeered and booed Cecil B. Moore, president of the local NAACP, when he tried to stop looting at 23d and Ridge. People paid no attention to Stanley Branche, of Freedom Now, who stood on a box and pleaded, "Please go home!"

"The accident ward of Philadelphia General Hospital looked like a battlefield first-aid station," wrote the Bulletin.

Wounded cops limped in. Most had been struck by bricks or bottles. One was hit with a baseball bat, another smacked with a store mannequin.

Looting continued into daylight, destroying what hours earlier had been North Philadelphia's shopping strip.

People boasted they could walk in the rain from Broad to 27th and never get wet - so plentiful were the awnings of clothing shops, restaurants, and dry cleaners, among five hardware stores and a movie theater, the Liberty.

At noon Saturday, Mayor James Tate ordered a public curfew. Comedian Dick Gregory arrived, persuading a crowd of 1,000 at Ridge and Columbia to disperse.

As afternoon edged toward evening, police said they got new orders: Stop the looting. Clear the corners. Clubs are trump - an expression that meant, "Use your nightsticks."

In the darkness, gunshots rang out. Police were told to return fire if fired upon.

Ordered into the fray was Michael Chitwood, a 20-year-old rookie cop, four months out of the academy, not yet old enough to vote or drink. A cinder block crashed onto the hood of his patrol car.

People seemed to have gone crazy.

"The first night was overwhelming and scary, because I had no idea what was going on," said Chitwood, now superintendent of the Upper Darby Police Department. "Was I going to get home [alive] that night? The thing that amazed me was how people were destroying their own neighborhood."

What caused the riot?

Fifty years later, some blame racist white cops. But the first officer on the scene, Wells, was black.

Some blame the discomfort of a long, hot summer. But records show the heat of 1964 was middling. And on the day the riot exploded, the high was a relatively mild 82 degrees.

Some say the chance of violence grew as racial and economic pressures built to bursting, largely over discrimination, jobs, and housing.

"It's very easy to be frustrated among the 'haves' when you 'don't have,' " said Johnny Gossett, 72, interim president of the Universal Negro Improvement Association, a fixture on the avenue since the 1940s. "We could call it a riot, but I would call it a night of frustration."

John F. Kennedy was dead, shot down in Dallas. In Birmingham, police had turned dogs and fire hoses on protesters, and at the Sixteen Street Baptist Church, a bomb killed four girls.

"The streets are going to run with blood," Malcolm X warned in January 1964. "Whole sections of cities will be bright with flame. Black people are going to explode."

Freedom Summer turned violent in Mississippi, as earnest voter-registration workers were beaten and the Klan murdered James Chaney, Andrew Goodman, and Michael Schwerner.

"It seemed like the world was turning upside down," said Michael Needle, a Philadelphia lawyer whose father ran the Needle & Boonin pharmacy at 22d and Columbia.

In August, the Democrats met in seedy Atlantic City to nominate President Lyndon B. Johnson, who feared Bobby Kennedy might steal the prize in place of his martyred brother. Three days after the Democrats left town, the Beatles shook the walls of Convention Hall .

But violence was as much in the air as music.

Between mid-July and Labor Day, riots erupted in nine American cities. The disturbance here, though ruining, was mild compared to the bigger, deadlier riots that within four years would level whole blocks in Watts, Detroit, and Newark.

"This is a story that echoes across the nation," said Randall Miller, a historian at St. Joseph's University. "There were so many expectations - there's going to be a federal war on poverty, movement on civil rights, education. But in this place, those expectations were false expectations."

Unemployment among black Philadelphians was twice the city average. North Philadelphia had fewer libraries, health centers, and playgrounds - but more taverns - than other parts of the city. Inspectors judged half of the homes in the area as "substandard" for hazards that included cracked sewage pipes, exposed wiring, and broken toilets.

On Columbia Avenue, store owners were nervous, trying to hold on.

Even before the violence, the better-off were fleeing the area. From 1950 to 1960, the white population fell 81 percent, 70,783 to 13,194. The black population surged 50 percent, from 94,609 to 142,396.

When the riot came, many merchants saw it as an anti-Semitic assault - they weren't wanted. Within 25 years, the number of businesses dropped from 158 to 57.

Almost anyone who could afford to leave would go - including nearly two-thirds of blacks.

"The neighborhood isn't a neighborhood now," Gossett said. "It's a campus. It's a Temple campus."

Kenneth Scott drove west on the avenue last week, pointing out wrecked buildings that, as stores, once gave life to the street. He nodded toward something else, too:

New houses, lots of them, many with garages and front lawns as green as any in a leafy suburb, built for low- and moderate-income residents.

The Beech Cos., of which he's president, strives to revive a neighborhood that many gave up for dead. The firm developed 1,200 housing units and plans to start on 1,000 more within two years.

"The prospects," he said, "are great."

That doesn't mean easy. It's taken Beech 25 years to get this far. Change is slow and obstacles are many. Attracting a supermarket and bank branch was arduous.

Often, what people know about the area isn't good: That rioting wrecked the place. That Harrison "Marty" Graham lived there, evicted from his home in 1987 because of the stench - which turned out to come from the bodies of seven dead women.

Hollywood Shoes, its entrance an antique whirl of tile and glass, is one of the last Jewish-owned stores on the avenue.

"Before the riots there was hustle-bustle, a lot of life," said Jeffrey Lauren, who runs the store founded by his grandparents. "Now there's no life."

Scott believes that will change - and sooner than later. That the neighborhood has assets beyond land, such as the Wagner Free Institute of Science, founded in 1855.

The goal is to attract families to settle. Businesses will follow. That it's a long-term endeavor shouldn't surprise anyone.

"It didn't fall apart overnight," Scott said. "And it doesn't come back overnight."

By Sunday morning, there was so much glass on Columbia Avenue that it crunched underfoot.

Scattered looting continued during the day as the riot burned itself out.

By then, pharmacist Larry Needle was in Atlantic City, to take his son to the Beatles concert. He had spent Friday night inside Needle & Boonin, protecting the store.

"I was sure they wouldn't touch it if I was there," son Michael, 60, recalled his father saying.

He was right, though the pharmacy survived for another reason, too. It had three phones - a veritable nerve center in the age before cellphones. Cops constantly went in to make calls, their presence dissuading looters.

The pharmacy stayed for decades after the riot. Larry Needle sold the business in 1997 and died four years later.

Today at the riot's Ground Zero is a rotting, empty building.

"It's so wrecked, it can't give you any memories," Michael Needle said. "One of these days I'm going to learn that it's been demolished."

Staff writer John Duchneskie contributed to this article. Some information came from the Temple University Special Collections Research Center.