Explaining Interior Urbanism

Interior urbanism refers to the design of interior spaces that are so large that they begin to act like cities.

Examples

Examples include large airports like Hartsfield-Jackson International, cruise ships, super-regional malls like the Mall of America or King of Prussia Mall, along with underground subway stations and connections such as New York’s Penn Station. If you’ve ever been to the Paris hotel in Las Vegas, you’ve likely looked up at the ceiling and seen the painted clouds and then walked up to an “outdoor café” all the while remaining indoors.

The Chicago Pedway covers five miles, connecting 40 blocks, and 50 buildings. The CNN Center in Atlanta has a post office, police station, restaurants, a hotel, and business offices all under one roof.

I earned my bachelor’s degree at Syracuse University. The City of Syracuse averages 128 inches of snow annually and is frequently considered the snowiest city in the country. When I was a student there, I learned that they have a system of underground tunnels that connect various campus buildings such as dormitories and dining halls so that students can avoid having to put on their full winter gear just to grab breakfast. For safety reasons, the tunnels were eventually shut down.

Similarly, The Minneapolis Skyway uses pedestrian bridges to connect over 80 downtown buildings, allowing people to remain indoors and out of the harsh Minnesota winters. An issue with this approach to connecting privately owned businesses is that when a building closes down at night, people lose it as an access point. No longer can they cut through one building to get to the next. They need to find an alternative route, either using other connecting bridges or venturing outside, even if just briefly.

In Philadelphia, there is a popular destination known as Reading Terminal Market. This center of commerce has a myriad of different businesses all under one roof including multiple diners, several small lunch spots, a butcher, a bookstore, a place to get your shoes shined, bakeries, a vitamin store, seafood markets, chocolatiers, and over half a dozen Pennsylvania Dutch (Amish) retailers.

On a smaller scale, you can even think of a convention hall as a form of interior urbanism. Consider how booths are put up along rows that mimic streets. Visitors walk up and down an aisle visiting booths on either side much like they would visit retail shops on either side of a sidewalk outdoors. Corner lots are generally allotted greater value to retailers, and the same is true for convention booths that have a corner location offering greater visibility.

Planning Considerations

Interior urbanism can occur inadvertently or intentionally. Often these spaces begin as nothing more than a connection between two distinct spaces. In Philadelphia, where I used to live and work, there is an underground subway system. In Center City (downtown), there are tunnels that connect some of the different stations. At one point there was nothing more than two distinct stations and an empty corridor connecting them just below the city streets above.

But over times, indoor development begins and spaces like the one in Philadelphia grow. Small retailers such as a coffee shop and a newsstand may be the first to emerge. Later, a fast-food restaurant, a deli, a clothing store, and an art gallery may spring up. Eventually the space below the ground begins to mimic the space above ground with retailers all along the way as you travel from one subway station to the next.

Other times, interior urbanism is purposeful and likely done with the intention of addressing an issue, such as providing city like amenities in a location notorious for bad weather.

Whether, one of these spaces naturally develops over time or is more purposefully created, planners and developers have several considerations to keep in mind. For example, they need to build around existing subway lines, support columns for buildings, sewer systems, and other forms of city infrastructure.

Concerns with Interior Urbanism

One complaint that some people have with these often massive interior spaces is that they more easily lose track of time. Without the ability to look up at the sky, it’s more difficult for our bodies to sense the passage of time.

The health of buildings and indoor space also becomes increasingly important. For example, at a time when we’re still dealing with the effects of a global pandemic and a virus that’s primarily spread through the air, we’re reminded of the importance of ventilation and indoor air quality.

Another concern is that the success of indoor cityscapes can lead to the pulling away of people from other parts of the city, similar to how a big box retailer like Walmart is often blamed for the loss of customers that would otherwise frequent smaller mom and pop stores. An out-of-town visitor may not be aware of the existence of one of these “hidden” interior networks and may simply see outdoor city streets that looks abandoned, failing to realize that the life the city lies elsewhere.