Chris Taylor peered down the street at the house. It was a vacant. And it was a problem.

He'd been getting calls for weeks about this property, about the teenagers hanging out there, the drug dealing and prostitution. He dialed a number, placed his cell phone against his ear, and began walking around the side of the building toward the alley.

As Taylor's phone connected to the person on the other end, he saw a door open. A young man walked out and pulled his hoodie over his head, casting a shadow on his face.

Standing 6-foot-1, Taylor was significantly bigger than the teen. But he was alone. And he was unarmed. And this was an alley in West Baltimore.

The teen kept his hand in his pocket as he approached.

Taylor hesitated.

"I think you're f---ing lost," the teen told Taylor.

In 2006, Taylor, then a 30-year-old Pennsylvania transplant, moved to Union Square. On his block, more houses were vacant than occupied. But he and his wife, Megan, loved the old house they bought in an area once inhabited by Baltimore intelligentsia, such as H.L. Mencken. And they weren't about to leave.

The couple didn't know it at the time, but Union Square was about to join a handful of neighborhoods bucking the trend of decline in Baltimore. After decades of residents fleeing for the suburbs, fewer and fewer of Baltimore's neighborhoods resembled the kind of place to which anyone would want to move. But for Taylor, Union Square was just the opposite: a place with cheap housing, proximity to downtown and a ton of promise.

So what if nearly half the houses were vacant? Union Square was about to start forging a comeback.

Taylor fixed his eyes on the youth and took the phone from his ear. On the other end was Southern District Commander Maj. Scott Bloodsworth.

"I've got the police commander on the phone," Taylor says he told the teen.

The young man's eyes widened.

"This is my neighborhood," Taylor said. "You're the one who's lost."

Minutes later, the cops arrived and placed the teen in cuffs. As for the vacant house?

"That's the good news," Taylor said. "It's currently under construction."

The vacancy problem

If Baltimore has a fundamental problem, it's represented by the vacant house: 47,000 of them — to be exact — about 16 percent of the city's housing stock. They're the result of Baltimore's population decline from 950,000 people in 1950 to 620,000 today.

The vacant house is an invitation for crime and litter to increase and a sense of community to decrease, activists say.

"The vacants are a huge, key issue," says Adam Van Bavel, a community activist from Pigtown, one of Baltimore's better-known transitional neighborhoods.

When Van Bavel moved to his block in Pigtown in 2007, only five of the 25 houses were occupied. Drug dealers used the vacants on either side of him. Now, most houses are occupied — including four vacants in the last year taken over by homeowners.

"Pigtown is one of those neighborhoods that could have easily been a Canton or a Federal Hill 10 years ago, but for some reason it wasn't," he says. "I can tell you that the residents of the neighborhood are doing everything we can to get more people moving into Baltimore City."

Since 2008, only 14 of Baltimore's more than 225 neighborhoods have sold more houses each year than the previous year. One of those is Union Square. That puts the tiny South Baltimore neighborhood with its $61,000 median home sale price in 2010 in the same category as Federal Hill ($285,000 median home sale in 2010) and Butcher's Hill ($250,000 median home sale).

For a neighborhood to consistently attract more residents, it needs to offer safety, cleanliness and a sense of community. And to build such a community, neighborhoods often need a leader.

Rosemary Wakeman, director of the Urban Studies Program at Fordham University, said younger, more daring people are often the first to start a wave of revitalization in a neighborhood.

"Often, the artist community makes up the pioneers," she said. "I think individuals can make a difference when they act as a functioning community. You have to have community leadership that can lobby for better services in a sustained way over time."

It's by no means an easy task for those who take on the challenge. Such urban pioneers often risk their time, money and safety in such an endeavor.

Taylor recently finished his fifth year as president of the Union Square Community Association and challenged for a City Council seat but lost. Sometimes, he thinks there might be something wrong with him for even undertaking such a mission in the first place.

"I don't know if we should be lauded or put in an insane asylum," he says.

Just ask Sebastian Sassi, who worked for years to try to remake Pigtown before deciding to move out. A hot neighborhood for investors a few years ago when it began a transformational period, Pigtown's home sales have regressed recently.

But few fought as daringly as Sassi during that time. Sassi created a website, Pigtown John Watch, to try to embarrass the johns and prostitutes into leaving. He got a right-to-carry permit and began to walk the streets with another resident, Nathan Flynn, doing patrols.

That was until someone shot what appeared to be a bullet through the window of Flynn's car, and Flynn later decided to move.

Finally, earlier this year, after his wife had a baby, Sassi joined him in getting out of Pigtown.

"It just didn't seem a worthy risk to my child to have me keep living there," he writes in an email.

"Baltimore has made it clear they don't value taxpaying families and our safety," he says. "They're trying to save places that are beyond saving and in the process losing places that can be saved."

Van Bavel, who's still bullish on the neighborhood, doesn't blame the police, but does think the city and the court system could do more.

He gets upset when he sees trash collectors leaving cans strewn through the neighborhood. He worries about repeat offenders who are let out on the streets.

"We've got the community and the police department working. The city and the legal system aren't," says Van Bavel, who is running a write-in campaign for City Council. "These people go in there and it's just release, release, release. That's why you're seeing middle class flight."

Operation smackdown

Taylor knows how difficult it can be to turn around a neighborhood.

The former teacher decided upon moving into Union Square that remaking the neighborhood would be his goal. He began buying and rehabbing the vacant houses.

But there were some problems bigger than just rehabbing houses. A drug gang named "Smackdown" ran a nearby corner.

"They were an intimidating bunch," he says.

The real breakthrough came in 2007 when Baltimore police and the Drug Enforcement Agency busted eight members of the "Operation Smackdown" gang, charging them with dealing about $20,000 of heroin a day.

With fewer dealers around, more people began to move in. And with more signs of a burgeoning community, Union Square became a less attractive place for dealers to set up shop.

Though he often worked with police, Taylor's fight for his neighborhood sometimes put him at odds with officers. In 2009, Taylor was arrested and accused of interfering with a police investigation after two girls reported to him that they were groped by a man in the neighborhood. Unhappy with what he perceived as an officer's lack of investigation, Taylor and the officer exchanged some heated words and Taylor found himself in the back to a patrol car.

Prosecutors eventually dropped the charge, and Taylor says the incident left him without any hard feelings toward the police department.

"Two days after, I went to officer appreciation day," he says.

Wakeman, the Fordham professor, says neighborhoods in transition not only need dedicated residents but businesses and government to get on board.

Louis Miserendino, a visiting fellow at the Maryland Public Policy Institute, thinks community leaders should be afforded the same low tax rates given to big developers. He says the current tax code removes incentive for improvement.

"If your house is in a transitional neighborhood, and you let it go vacant, your bill goes down," he said. "If you improve it, your bill goes up."

Baltimore has the Vacants to Values program, which encourage residents to buy and rehab some 700 properties, including a handful in Union Square. For as low as $3,000, a resident can buy a house to rehab in the neighborhood. Though the plan is sometimes criticized as underperforming, Mayor Stephanie Rawlings-Blake has instituted incentives to bolster Vacants to Values – including $10,000 in down payment and closing cost assistance to the first 50 buyers.

'This is a nice neighborhood'

In Taylor's five years as community association president, the group has grown from about 25 members to more than 100.

"The minute you get rid of the vacants, it cleans up the community," he says. "If you have a block with 14 vacants you're going to be fighting a battle every day."

He's had help over the years.

Andrea Leahy, 46, moved in several years ago. She started giving flowers and plants for the front steps of each new resident who moved in. It's a small gesture, but it sends a message. Somebody who takes pride in her community lives here.

Other association members pass out trash cans so no one has an excuse for littering. Sometimes a new renter will begin to let trash accumulate in their area. They'll get a knock on the door and a reminder to use that trash can they got upon moving in.

One clear day in the neighborhood, Thomas Pointer, 41, a writer, and Danielle Campbell, 27, a new resident, stand outside talking with neighbors

Campbell says she thinks the neighborhood is one of the city's best. Pointer says he notices changes.

"It's a big difference. This is a nice neighborhood now," he says.

The vacancy rate has dropped from nearly 50 percent to almost 20 percent. The neighborhood hasn't had a homicide in three years.

Even with the progress, the neighborhood still has its issues.

The residents point to a corner store that stays open 24 hours a day and becomes a haven for drug users at night, Taylor says, as he picks up trash. Last month, there was a handful of property crimes. Still, he says, the greatest challenge is attracting people to renovate and move into the houses still vacant.

"It took 60 years to get this way," he says. "We're not going to fix it in five years."