Here's what could happen to America's hundreds of dead malls

As one of the first post-war suburban shopping centers in the US, the Northgate Mall in northern Seattle defines classic mall architecture.

Its architect, John Graham Jr., pioneered the dumbbell, big-box shape for malls, in which two rows of stores face each other and two department stores anchor each end. Graham also gave Northgate Mall a grocery store (which later became a food court) and a huge parking lot. In the decades that followed, malls around the country copied Northgate's layout, which became the model for most American malls throughout the late 20th century. 

This design may not be working in the 21st century, however. Hundreds of malls and thousands of mall-based stores have shuttered in the past two decades, and many more may close within the next 10 years.

Traditional malls need to transform themselves to stay alive, and many are making changes to attract more business — including Northgate.

Developers are now turning many of the mall's parking spaces into a light rail station, which will connect the neighborhood to downtown Seattle. Other parts of the lot have been turned into LEED-certified apartments, senior housing, a medical center, more retail space, and a bioswale that keeps runoff away from the nearby creek. Earlier in 2017, Northgate's Sears closed and turned into a public library.

Malls of the future have an opportunity to fulfill other community needs besides commerce, June Williamson, a City College of New York architecture professor and the author of "Retrofitting Suburbia," tells Business Insider.

"Northgate [Mall] evolved as the neighborhood around it — which was mostly built in the '50s, '60s, and '70s — did," she says. "People are tired of the traditional mall."

Here are what may become of the many failing malls of today:

SEE ALSO: The retail apocalypse has officially descended on America

Before: The department store

Nearly every major department store (including Macy's, Kohl's, Walmart, and Sears) has shuttered stores in recent years to reduce losses from unprofitable locations and the rise of online shopping.

The US also just built too many malls, Williamson says. In the mid-'90s, the number of American malls peaked at around 1,500. Today, there are only about 1,000 left.

As more new malls get built, department stores (which often pay a large part of the lease) will move out, making it harder for the mall to survive.

"The development climate of malls were driven less by demand and more by opportunity," Williamson says. "As new centers get built, anchor stores are lured away, and a cannibalization process begins ... Only so many consumers are going to malls, and they will flock to newer ones. If developers build a new mall, they are inevitably undercutting another property. So older properties have to get re-positioned every decade, or they will die."

After: Fitness centers, churches, medical clinics, and data centers

Closed department stores will likely become other businesses that can benefit from the large square-footage, like fitness centers, churches, offices, public libraries, and even medical clinics, Williamson says.

The number of walk-in clinics in malls rose 15% from 2011 to 2016, according to the Urgent Care Association of America. Last year, Bloomberg reported that a third of all urgent care is now located inside shopping centers.

In 2007, the 100 Oaks Mall redeveloped one of its department stores into the Vanderbilt University Medical Center, which leases over half of 850,000-square-foot building. (The other half is still retail space today.)

In late 2016, the Milpitas Planning Commission in California also approved a plan to turn the abandoned department store in the Milpitas Town Center into a 24-hour gym.

Before: The food court

Retail stores are not the only mall businesses that are struggling. Those in the food court are having a hard time, too.

In 2014, Sbarro — the Italian chain that was a food court staple — filed for bankruptcy, and closed 155 of its 400 American locations, most of which were in malls.

As The New York Times noted at the time, "The company is in financial trouble because one of its big bets on real estate — that Americans will keep going to mall food courts en masse — has turned out to be wrong."