It seemed almost inevitable, even back in high school when his nickname was "the Mayor."

He wouldn't officially get the title for almost 30 years, but Richard M. Daley, son of the last big-city boss who ruled Chicago for more than two decades, followed his father's footsteps to the fifth floor of City Hall. Over 21 years, he brushed aside all challengers and put his unique mark on the nation's third-largest city.

Then, last week, he stunned the city the Daleys had made their own, declaring he'd leave at the end of his sixth term next spring. By then, he'll have served about five months longer than his father, Richard J. Daley.

Daley's departure marks a turning point in Chicago — the passing of a long chapter in history in which a father and son have reigned over a city for 42 of the last 55 years. They've wielded enormous power (sometimes as kingmakers, often as autocrats), shaped a glittering skyline and, at one point or another, decided everything from who ran for Congress to who collected quarters from the municipal parking meters.

It's the kind of record not likely to be replicated.

"There are not many mayors who've been institutions ... not many families who have been institutions," says Alan Gitelson, a political science professor at Loyola University of Chicago. "You're really seeing the end of an era. ... It's going to take awhile, if ever, before you ever see this kind of political empire in the city. It may happen, but I don't predict it."

The Daley legacy, father and son, is one of grand ambitions.

It includes a downtown that is a forest of glass and steel skyscrapers designed by some of the biggest names in architecture, befitting a city whose lakefront was shaped by Daniel Burnham. The famed architect's advice to posterity: "Make no little plans." The Daleys took that to heart.

It was under Richard I — as the late mayor is sometimes dubbed — that Chicago saw the rise of the Willis (nee Sears) Tower and the John Hancock Center, the University of Illinois campus west of the Loop and the expansion of O'Hare International Airport.

It was under the son — aka Richard II — that the city saw a widespread "greening" with giant planters exploding with flowers; the redesign of Soldier Field, home of the Chicago Bears; and the unveiling of Daley's crowning achievement, the spectacular (and costly) Millennium Park with its soaring steel ribbon bandshell designed by architect Frank Gehry.

"They called Richard J. Daley the great builder," says Bob Crawford, retired political editor for WBBM radio who covered both Daleys. "He loved putting up tall buildings that changed the skyline. He knew those symbols were important to his claim this was the one city in America that worked. Richie had some of that in him (but) ... he was more sensitive to the livability elements. He spent a lot of time on cultural developments, museums, reviving the theater district, beautifying the city."

Both Daleys could get what they wanted because they cracked the whip over the 50-member City Council. In the iron-fisted era of the first Daley, critics were literally silenced — their microphones were occasionally shut off at council meetings when they said something that annoyed the mayor or his allies.

"Not only did they want control, they enjoyed control," says Paul Green, a political scientist at Roosevelt University. "Everything that went in and out, it was mayor's fault or his success. There was little fuzziness about both mayors. When it comes to running things, including taking tremendous risks, everyone knew who was in charge."

The son took that principle to extremes when state officials balked at his plan to close Meigs Field, a small lakefront airport, and turn it into a nature preserve. Daley ordered in the bulldozers, and in the pre-dawn darkness one spring night in 2003, the runway was destroyed.

Critics howled, but Daley stood defiant. He declared straight-faced at a new conference that closing the airport would "make Chicago a safer city" from terrorist attacks, though he conceded there had been no threats. He said voters wanted him to make decisions. "They didn't elect me to be a lover boy," he said.

While the mayor has never hesitated to flex his political muscle, he's widely perceived to be more reform-minded and more inclusive than the first Daley, operating by coalition rather than a monolithic machine.

"He's a much more cosmopolitan figure than his father," says Dick Simpson, a former independent alderman, critic of both mayors and a political science professor at the University of Illinois-Chicago. "He marched in the Gay Pride Parade. His father would have turned over in his grave."

The mayor also has shown a willingness to deal with race and ethnic issues in way the elder Daley didn't, says Gitelson, the Loyola professor. "He had a level of compassion that was much broader than his father's," he says.

But in many other ways, the two men seem more similar than different.

Both were fierce Chicago boosters. The younger Daley launched a big money, high-profile — and ultimately unsuccessful — bid to land the 2016 Summer Olympics.

Both developed reputations as detail men, riding to work carrying little notepads, jotting down things they saw that warranted attention, then calling department heads when they arrived at City Hall to make sure someone tended to the problem.

And both believed it was important to keep an ear to the ground. "Even if the grapevine shook a little bit, they wanted to know what shook it, no matter how low in the city structure it was," Crawford says.

Both mayors also have shared something else: Corruption scandals that dogged them and raised questions about whether they ignored graft and greed in their administrations. One of the mayor's former commissioners was found guilty this summer of hiring fraud in a retrial; a patronage scandal also sent four aides to prison in recent years.

"When people tell me Chicago is the city that works — when you have that much corruption ... there's no way you can say it truly works," Crawford says.

One distinct difference between the two men is that unlike his son, the first Mayor Daley actually held two jobs that increased his influence far beyond the city.

As chairman of the Cook County Democrats, he presided over a vast army of ward committeemen and precinct captains, most of them with jobs on the city payroll they held on to by getting out the vote in big numbers for the party-backed candidate on Election Day. It was the classic, old-time political machine and at one time, considered the most powerful in the nation.

It made Richard J. Daley a force in national politics.

His precinct captains pounded the pavement to help John F. Kennedy eke out a razor-thin win in Illinois in 1960 amid grumbling and rumors that some votes had been squeezed out of graveyards. And in 1968, when Bobby Kennedy was seeking the presidency he was reported to have said, "Daley means the whole ball game."

It was in 1968 that the elder Daley suffered one of the most dismal moments of his career at the Democratic National Convention when blue-helmeted police, swinging nightsticks, pummeled and bloodied Vietnam war protesters, who chanted "the whole world is watching.'" An official report later called it "a police riot."

It took 28 years for Chicago to get another Democratic National Convention. By then the younger Daley was in City Hall, and the gathering went off without a hitch.

The Daleys were not the first father-son duo to lead Chicago. The Carter Harrisons — Jr. and Sr. — had that distinction in the late 19th and early 20th centuries.

But the Daley name is now so synonymous with Chicago politics, it might as well be stitched into the city flag.

When Richard J. Daley died in 1976 and was replaced by an alderman named Michael Bilandic, neighborhood children called him "Mayordaley Bilandic."

Green, the political scientist, says his grandmother "didn't understand why anyone would run against him."

Both Daleys grew up in Bridgeport, the neighborhood southwest of the Loop that was once was the seat of the stockyards where the father briefly worked before he entered politics. The neighborhood, packed with city payroll employees, has sent five of its sons to the mayor's office. Like his father, the current mayor is a devoted Catholic who puts family first and roots for the neighborhood team — the White Sox.

Both Daleys had political careers first as state legislators and then moved to county offices with plenty of patronage jobs in them before running for mayor. (It took the younger Daley two tries. He lost the Democratic primary in 1983, facing Jane Byrne, the city's first woman mayor, and Harold Washington, who became Chicago's first black mayor.)

Daley, now 68, not only inherited his father's job, but some of his most distinctive personality traits: a tendency to mangle the English language and a short fuse that flares on occasion with reporters.

It was the late mayor who once told reporters they could kiss the mistletoe hanging from his jacket when they questioned him about a deal that turned over city insurance business to an agency where one of his sons worked.

And it was this mayor who recently responded to a reporter who questioned the effectiveness of the city's strict gun control law by picking up a a rifle with a bayonet from a collection of police-seized weapons and saying: "If I put this up your butt, you'll find out how effective it is."

Daley quickly said he regretted the remark and was just trying to shock reporters and get them to focus on the responsibility of gun manufacturers.

In announcing his decision not to seek a seventh term, Daley said it simply was time to go. Some speculate his wife's long bout with cancer and his plummeting poll ratings as possible reasons.

Crawford remembers a conversation he had with the mayor after he won his third term when the radio journalist asked him how long he'd serve and if he'd exceed his father's tenure. He says the mayor replied he'd remain in office until he didn't have the fire in his belly any longer. then added, "I'm not going to let the job kill me the way it did my dad."

There's little doubt the mayor faces financial pressures that didn't exist during his father's era.

In the 1950s, Chicago was a relatively prosperous blue-collar city with a healthy manufacturing base. The mayor could turn to the federal government for financial help with big-ticket projects. Half a century later, Daley shepherds a city that is struggling like so many others — grappling with high unemployment, far fewer factory jobs and massive red ink. The projected budget deficit is $655 million.

He's also facing problems that have lingered for decades — problems that some blame on his father.

The elder Daley, who drew his core ballot box support from Archie Bunker-style blue collar voters, has long been blamed for fostering racial segregation by isolating the black poor population in public housing high rises, many of them constructed next to busy expressways. The buildings quickly deteriorated into reeking, crumbling bases for drug selling street gangs that have haunted this city for decades.

"He used almost every instrument of government to hold back the growth of the black population in cooperation with the real estate industry," says political strategist Don Rose. "By building public housing where and when he did, he set in concrete the segregated patterns of Chicago."

The younger Daley has spent the last decade tearing down those high rises. But there are complaints that former residents are being resettled in communities as dangerous as the ones they fled.

The mayor also is widely credited with healing some of the city's racial wounds. He has doled out a considerable slice of the political pie to the black community, hiring blacks as well as Hispanics for key positions. He has never faced a tough black opponent on Election Day

"The racial divide is not the way it was. There's no question he played a role in that," says Dawn Clark Netsch, a former legislator who served with Daley in the state Senate and was one of a few independent liberals to support his early candidacies as state's attorney and mayor. "He made a very conscious effort to spread the city goodies around. That clearly made a difference."

Daley's boldest move as mayor has been to take control of the city's troubled public schools. Dozens of new schools have been built and a series of reforms put into place, including ending social promotions. But progress has been slow with many schools still lagging far behind, their students posting poor test scores.

As much as the Daleys have accomplished, some say the corruption endemic to this city will forever haunt them.

"They would tinker at the edge of reform, but they were never willing to cross that boundary into that area where they would undergo the structural changes that would get rid of the corrupt influences," Crawford says. "They somehow couldn't bring themselves to do it. I think they thought it was too politically risky. They made some sort of accommodation with that."

When people ask him to sum up the Daleys, he says he offers a short reply.

"I call them great mayors," he says, "but remember the price."