The downtown redevelopment plan took five years — from the first communitywide charrette to approval by the five-member County Council in 2010.

In the years before that, ownership and management of downtown changed significantly. General Growth Properties, the real estate trust that develops and owns shopping malls across the country, bought the Rouse Co. in 2004 and went bankrupt in 2009. As a result, General Growth lost its place as the downtown's dominant landowner and developer to the Howard Hughes Corp., a spinoff created in the bankruptcy.

Rouse died in 1996 at nearly 82 years old, but his "city" idea survived, and with it the hope for a lively downtown.

"The Town Center was supposed to be the center of it; it was supposed to be the hub of Columbia," said County Councilwoman Mary Kay Sigaty, whose district includes downtown. Instead, the mall, which opened in 1971, came to dominate the scene. During years of debate on Town Center redevelopment, there were some who wanted to do nothing, but also many — especially young people — who were eager to see the downtown become a lively urban place, Sigaty said.

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"For those of us who live nearby, the concept of having the center of our community be a suburban shopping mall, it's sad," said Sigaty, who has lived in Columbia since 1972.

Rouse in those days was touting malls for their potential to serve as vital community centers, but his team also had notions about turning the lakefront into an active center. They explored creating an amusement area modeled on Tivoli Gardens in Copenhagen, but there weren't enough people around yet to make that work, said Robert Tennenbaum, the architect-planner on the original design team, who still lives in Columbia.

Tennenbaum and Finley both recalled that there was never a plan to design the Town Center in a street pattern more or less like a conventional city center. A mall was always seen as the downtown center, they said.

Today, the plan to reshape downtown attempts to strike a balance — building new streets to connect areas that are not connected, encouraging more walking and bus commuting and less driving, and bringing more people into the center. The county is considering plans to develop Symphony Woods, next to Merriweather Post Pavilion, as a cultural park.

Even if thousands of new residential units and millions of square feet of new office, retail and hotel space do materialize, the mall will still be a focal point. The Mall in Columbia, now 1.6 million square feet, is in the midst of adding 40,000 square feet and renovating 30,000 more.

The first part of the new mall space is expected to open Friday with a Soma Intimates store featuring lingerie and beauty products. A Secolari store, specializing in gourmet olive oil and vinegar, is scheduled to open in late November.

Next to the mall, the Metropolitan Downtown Columbia apartments, with 380 units in two buildings and stores on the ground floor, is expected to open next year.

Darrell Nevin, a commercial real estate agent in Howard County, gives the Howard Hughes Corp. credit for making the commitment to downtown, and especially for landing Whole Foods for the lakefront building that used to be the Rouse Co. headquarters.

"That's huge," said Nevin. "When I talk to people about what's happening in Columbia, there's a lot of excitement."

Rouse's vision will be recalled with an exhibition of photographs, artifacts and a reception tonight in Town Center at the Columbia Archives, a repository of local history.

Tennenbaum imagined that if he were he still around, Rouse might be skeptical about a few details of road layout and the amount of retail in the redevelopment. But all in all, he would applaud the plan for downtown.

"I think he would have been pleased with the concept of making it more walkable," Tennenbaum said. "I think he would love it."

Note: An earlier version of this story misstated the rank Columbia would hold among Maryland cities if it were incorporated.  It would be the state’s second largest city.It has been corrected here.