Marielle Segarra

When a construction fire damaged Pittsburgh's Liberty Bridge last month, the Pennsylvania Department of Transportation closed it for 24 days to do repairs.

By 2050, 70 percent of the world's population will be living in cities, according to a United Nations estimate. Mayors could be more influential than ever.

That's why it's important to start training city leaders now, says Jorrit de Jong, faculty director for the Bloomberg Harvard City Leadership Initiative. 

Pennsylvania has voted Democratic in the last six presidential elections. But this election season, analysts say it's possible that the state will swing Republican. 

A new study finds a link between the racial makeup of Philadelphia neighborhoods and the number of primary care doctors who work there.

The study, conducted by researchers at the Christiana Care Health System, the University of Pennsylvania, Boston University, and the French Institute for Agricultural Research, measures primary care doctors per resident in Philadelphia's census tracts.

Pennsylvania has more trash in its landfills, per person, than every other state, except Nevada. There are 35.4 tons of trash for each person in the state, according to ananalysis of data from the Environmental Protection Agency's Greenhouse Gas Reporting Program, conducted by the energy company SaveOnEnergy.com.

On a Wednesday evening, about 30 people — mostly kids — sit poised on their bikes on a street in downtown Reading.

It's 6 p.m., and they're about to head out for their weekly ride through the city.

A man in a white t-shirt goes over some safety rules.

"Be aware of your surroundings," he says. "No stupid stunts, none of that. And please stay together."

With that, they take off, to the tunes of Marc Anthony's "Vivir Mi Vida," playing from speakers on the back of one guy's bike.

  Early-stage companies need cash. The state is helping them get it, by giving them tax credits they can sell.

On Thursday, the Department of Community and Economic Development spoke to about 35 people, many of them early stage tech company CEOs, about the Keystone Innovation Zone program. 

Philadelphia will use the grant, from the nonprofit Living Cities, to improve racial equality in its government operations. The city will focus on workforce development for people between ages 16 to 24.

That seems like a big task for a small sum.

More than 53,000 people in Pennsylvania live in government-assisted nursing homes, hospitals or institutions. But in a new plan, the state Department of Human Services said it's hoping to move a lot of those people to apartments or homes.

Tommy Joshua was working in the garden when a guy from his neighborhood rode by on a bike and gave him some bad news.

"Some dude, some like arbitrary man," Joshua said, "told me straight up, 'Yo dog, they got a plan to like, take this whole jawn over. You're doing all this in vain.'"

More than 100 water systems in Pennsylvania have had lead levels above a federal threshold at least once since 2013, according to an Associated Press analysis of the data.

It's 1957. Dr. Herbert Needleman is on his way to see a three-year-old patient at the Children's Hospital of Philadelphia.

Needleman is a young doctor, about six feet tall, with brown eyes and dark hair. This is the first case of lead poisoning he's ever seen.

When he shows up, the girl is not in good shape. Her eyelids are drooping. Her pulse is slow. She's not making a sound.

Concentrated poverty is growing across the country, according to a report from the Brookings Institution.

Since the recession, more people live in neighborhoods where at least 20 percent of residents fall below the poverty line. 

At Kutztown University, a lot of students live near campus.

But not Shannon Peitzer.

She's a senior. And every morning she spends at least half an hour driving to school from her apartment.

Around Pennsylvania, you'll see lots of historic homes: romantic 18th century red brick houses, stately Victorian-era mansions and dense rowhomes built for industrial workers. 

The state's old houses, half of which were built before 1959, can give a neighborhood character. But they can also cause a lot of problems.

Some of the homes are filled with health hazards like lead paint and ancient wiring. Others are simply falling apart with age.

And many residents can't afford the repairs.

As the industries along urban waterfronts have faded, big cities like Philadelphia and Pittsburgh have come up with robust master plans — and significant funding — to connect people with their rivers.

But what can smaller municipalities with fewer resources do to revitalize their waterfronts?