Today, Summit Hills Apartments in Silver Spring would not be built. No planner would recommend stacking 1,120 apartments on a 30-acre plot. No one would plan carpeted hallways, endless stairwells, and only the thinnest strip of swing sets for a community that would become known for its hundreds of children.

But in an unexpected way, the plain brick complex on 16th Street NW near the District line has come to represent what Montgomery County used to be -- and what it is now becoming.

"The county is so much more diverse now. It's an urban setting, and Summit Hills reflects that," said Nikki McCausland, chief of Montgomery County's Office of Landlord and Tenant Affairs. "We're not just a county of wealthy homeowners, as the stereotype goes."

When they were built 30 years ago, the apartments were home to a largely Jewish, middle-class and adult population. There was a synagogue and a delicatessen on the grounds. Now county officials describe Summit Hills as possibly the largest and densest concentration of different cultures in the county -- and certainly one of the few remaining affordable residences for service workers and their children.

Twenty-five buses from different schools enter the complex each day. Where the kosher delicatessen stood is now a dry cleaners. In place of the synagogue is a day care center with 50 children -- some from Jamaica, Nigeria, Ghana, Guatemala and El Salvador.

As the county's minority population has grown (from 5 percent in 1970 to 15 percent in 1980), Summit Hills has achieved an unusual mix: Ninety-five percent of its residents belong to a minority group.

Some of the attractions of Summit Hills are its moderate rent ($595 for a two-bedroom unit, compared with the county average of $650), its spacious rooms and its option of three- and even four-bedroom apartments, the only four-bedroom units left in Montgomery, county housing officials said.

Determining just how many residents live in Summit Hills, however, is difficult. Even with the official count of 4,000, the complex qualifies as a small town. But often, the management discovers as many as 15 people living, against the rules, in a two-bedroom apartment.

"It's concentrated housing -- not good housing -- for 4,000 people," said Ronald Frank, vice president of Southern Management, the firm that bought the complex in 1979 and spent $6 million on renovations. "But there's more than 4,000 people there, I guarantee that."

With the planned revitalization of Silver Spring, with Summit Hill's prime location at the intersection of 16th Street and East-West Highway, and with the owners' continuing frustrations over vandalism and other problems, the long-term future of Summit Hills seems, at best, uncertain.

"What's interesting is what's going to happen," said Edgar Mantilla, the Hispanic outreach specialist for the county's human relations commission. "Where are these people going to go eventually?"

But for now, life at Summit Hills is sometimes entertaining, sometimes frightening, always in evidence.

"Twenty-nine years ago," said the elderly woman as she pushed the elevator button, "this place was a hot item.

"But that," she said dryly, "was 29 years ago. Now it's more like the League of Nations."

The woman was small and thin, her gray hair newly styled, her pale-blue dress immaculate. She didn't want her name used, she said, and she never tells her age. Now widowed, she has lived at Summit Hills since 1959.

"We had a young son and we came for the schools. That was the big attraction," she said, opening the door to her roomy, light-filled apartment. "And it was handy to live here -- my husband had a business downtown.

"We looked around and looked around, and the rooms everywhere else were smaller, and you get used to a big dining room." In 1959 the one-bedroom apartment rented for $135 a month; now it is $530.

Actually, Summit Hills has already achieved one comeback. During the 1970s, management problems led to two foreclosures and the deterioration of the complex, county officials said. By 1979, when Southern Management took over, 20 percent of the apartments were vacant or uninhabitable. Now, said county official McCausland, the apartments "are much better. We have to look at where it used to be . . . . "

A knock came at the elderly resident's door, and in walked her neighbor and friend -- a short, bespectacled woman wanting to borrow the new Danielle Steele novel they had checked out from the bookmobile. She is 82; her husband, 90. They, too, have lived at Summit Hills since 1959.

"Oh, it's going to the dogs," she said. "It's not a safe place to be in the evenings, let's put it that way. It's not the nicest place in the world."

"Well, Minnie, you have a husband," her friend said. "You have somebody who can drop you right off at your door."

"That's true," said the 82-year-old woman, "I haven't been to the swimming pool in 15 or 20 years, but it used to be beautiful.

"The fact is," she said, "we're too old to move, and that's the dirt."

School was out. The yellow buses lumbered through the complex, letting out 25 students at one building, 15 at another, a dozen more up the hill.

This was the social hour for the children of Summit Hills. Jose Sanchez, 9, wove his old black bike through the Datsuns and Impalas and vans in the parking lot. Naa-Kailey Botchway, 7, tagged along with her big brother Cliff, 10, and his friends as they attacked the remaining snow hills at the complex. At the side of a building, Anita Redman, 15, and two friends gleefully exchanged notes about "a snob we know who just got braces -- ha, ha, ha."

Redman, a sophomore at Einstein High School in Kensington, moved last year to a four-bedroom apartment with her Jamaican-born parents and her two brothers and two sisters. She quickly became friends with Anoko Zankli and Sharmaine Byrd, although they all go to different schools.

"It's a lot of fun here, but there's a lot of action, too," said Redman, who previously lived in the District.

"Yeah, the only thing that worries me is that drugs are everywhere," said Byrd, 15. "The police'll come and get somebody and we'll crowd around and watch."

County police at the Silver Spring station, however, said that Summit Hills is no longer considered one of their major trouble spots.

"There're still drugs and a few break-ins and robberies, but not like it used to be a few years ago," Sgt. John Straughan said.

For the three teen-agers, living among so many different cultures is exciting; all have picked up some Spanish from their neighbors.

"The little Hispanic kids, they hang with us. They're sweet," Redman said.

"Sometimes the older guys get on our nerves," said Zankli, 14, whose parents are from Togo and Nigeria. "They'll be drinking and they'll say, 'Hey, baby.' But we never have any real problems."

"People are kind of tolerant here," Byrd said. "Like, in the hallways, there'll be kids playing and nobody comes out and yells at us to be quiet . . . You have to live here for a while to see how fun it is."

"Yeah," said Zankli, "we're all equal."

At the new Las Americas market across 16th Street, Ricardo Carbajal was cutting thick, blood-red slices ofliver for the evening rush-hour crowd. Nearly all his customers come from Summit Hills, he said. They buy plantains and avocados, yellow cornmeal for tortillas, parents' magazines touting "El Superbebe," and jars of yellow ready-to-eat lupini beans.

"They usually come in little groups together because they are scared," said Carbajal, 31.

Carbajal's friend, a 29-year-old Salvadoran, leaned up against the meat counter and nodded agreement. A construction worker and the father of two small girls, he has lived at Summit Hills for almost nine years.

"It is close to the Metro, the stores, everything. You can take the Beltway around and go anywhere," he said. "And I prefer Montgomery County. The schools are good and there is less crime and I like the way my oldest girl is getting educated.

"But there are lots of people, lots of drugs, lots of problems over there," he said. "You can go into almost every building and see bunches of people in the lobby, moving around, doing what doesn't concern them, saying bad words to the kids. But it's like any other neighborhood -- you don't mess with nobody, nobody messes with you."

The man said he would like to live elsewhere, but not in another apartment. Like so many of his neighbors, he said, he has a specific dream.

"Every month you pour $700 down the drain and nothing's ever going to be yours," he said. "I have to start thinking about buying a house -- that's my next move."