As Far as the Eye Can See Space, History, and Baltimore's Alleys

This inquiry into Baltimore's interstitial spaces began in Rome in 2011. As a student living in the Eternal City I spent countless hours exploring by foot, without a map or plan, wandering at all hours through parks, bus stations, piazzas, and alleys, guided only by my senses.

Some of these wanderings eventually became well-worn pathways of mine, private destinations where I would take trusted friends, while others were traveled only once and labeled internally as unwelcoming or ugly. In these spaces I felt most acutely the texture of a place, its history, its contradictions, and its character. These were not the celebrated plazas or parks but the in-between places, the passages, courtyards, and back streets that seemed to hold a different and more intimate relationship with the life of the city around them. This intuition, that the spaces between things carry as much meaning as the things themselves, became the seed of this research.

Alleys are one such interstitial space. Woven into the oldest fabric of American cities, they have functioned as service corridors, home entrances, drainage channels, and gathering places for centuries. In Baltimore, their history is particularly dense. Alley homes housed the city's poorest residents, concentrating poverty, disease, and racial segregation at the interior of the urban block while wealthier inhabitants faced the main streets and parks beyond. These conditions made alleys both essential and invisible, vital to the functioning of the city while overlooked. That tension persists today. Alleys still serve as service corridors and neighborhood connectors, yet they are absent from Baltimore's pedestrian planning efforts and unconsidered in the redevelopment projects that are transforming the city's oldest neighborhoods.

To begin a methodological approach to studying Baltimore's alleys I mapped Baltimore's original alleys and their current conditions. My first step in this process was identifying Baltimore's oldest neighborhoods. I compiled a list of neighborhoods from which I then identified four of Baltimore's oldest to begin my study: Jonestown, Fells Point, Upper Fells Point, and Washington Hill.

I then used GIS software to georeference an 1896 Baltimore topographical survey commissioned by Baltimore City. Using the 1896 survey as a basemap, I then mapped every original alley in each of the four neighborhoods. After mapping the original alleys, I repeated the process with a 2008 topographical map produced by Baltimore City Dept. of Public Works. Through the process of mapping the existing original alleys in these four neighborhoods I produced nearly six miles worth of alleys to study.

To take my study into the field I used MerginMaps, a mobile mapping software which allowed me to make observations and updates to my GIS map then sync them to the larger project. I began walking the alleys, beginning with the oldest neighborhoods. As I walked each alley I took note of the entry condition to the street, the edge condition, the alley type as it applied to my previous observations, and I made general observations regarding the feeling of the alley and factors that contributed to these feelings. I also took around 700 photos of these conditions and any anomalies that presented themselves.

As I moved further north into newer neighborhoods I found a widening of space. I also wanted to visualize the visible perspective of the pedestrian, so I redrew and recategorized the edges depending on the ability for someone to see through, or past them. Red lines represent solid surfaces, cyan lines are blocked edges but still able to see through, an example of this is a chain-link fence, green lines represent open edges where the pedestrian could freely walk such as a park, a parking lot, or a patch of grass. This map again reinforced my field observations as there is indeed both more visual space and open space along the alley edges in the northern neighborhoods.

To better understand these alleys' relationship to their edges I identified three stretches of alley which exhibited the changing edge conditions. These were South Bethel Street, South Durham Street, and South Chapel Street. After reviewing the alley conditions, I chose South Bethel Street due to the contrast in edge condition. South Bethel St. is a ten-block stretch of alleys that passes through Fells Point, straddles a neighborhood called Perkin's Homes, and passes into Washington Hill. This alley contains a mix of edge conditions that aligns with the general pattern I identified across all alleys.

After selecting S. Bethel St. I made multiple site visits to better categorize and analyze its conditions. Part of this process was taking a photo of either side of the alley every 20 feet or so. I then took my photos and created photo collages of each side of each block of the alley. This helped me to better understand how space varies along the alley. By comparing the transects we can see that at the southern end there are more buildings immediately along the alley's edge while further north there is more blue sky and trees.

Used as a tool to convey the relationship between the built environment and the space around it, figure-ground diagrams use the color black to symbolize figure, or mass, and white space to symbolize the ground, or void plane. The famous use of this mapping technique is Giambattista Nolli’s map of eighteenth-century Rome, and thus the “Nolli Map” has become a common substitute for the figure-ground diagram.

Using Sanborn Fire Maps from 1914 and 1942, along with the 2008 topographical survey used in mapping the alleys, and observations from my field work, I created a series of four Nolli Maps showing the changing corridor of S. Bethel St. These studies uncovered a shocking discovery, while most of the southern blocks remained intact, a former block of rowhomes between Pratt and Gough Street was demolished and replaced with apartment buildings in the early 40s. To further appreciate these changes, I layered the maps onto one another and, through altering their transparency, was able to see the changes over time. This process revealed two contrasting focus areas which could be compared and studied to hopefully reveal the reason for the dramatic shift in edge condition.

This drastic shift in the urban infrastructure piqued my interest and sent me searching for the reasons behind it.

In Baltimore, during the early 1930s there was a push for urban revitalization through the clearance of "slums" or "blighted areas." Led by a committee formed by the State Advisory Board of the Public Works Association, this group identified areas that would benefit from rehabilitation through the destruction of existing infrastructure and introduction of public housing. While public housing was the advertised outcome and benefit there was also documentation that the project would preserve segregation in wealthier white neighborhoods.

Area 5, which is the block identified through my research, was identified as an area where black families were living next to white Polish immigrants, and so the eventual housing development, named Perkin's Homes, would be built for white immigrant families. Due to the restriction on white families, it is a certainty that no former tenants on this block of S. Bethel St. benefited from the housing projects.

Today, this block of S. Bethel St. is undergoing yet another transformation, citing strikingly similar reasons to its initial redevelopment including poor living conditions and a "blighting influence on the neighborhood." While green space and community health are main goals of this project, there is no apparent attention turned to the historic role that this neighborhood played in Baltimore's history, a history that is directly tied to the alley.

Placing photos of the built conditions of the western side by side across time reveals the drastic change and paints a picture of how different each of these alleys would be to walk down. Taken between 1938 and 1941, photos of the western edge of the Northern Block show the alley just before its destruction. Comparing them against a photograph taken in 2026 makes visceral what the Nolli Maps and models can only suggest.

Nolli Maps and photo collages helped to frame the differences between the two blocks through the perspective of a pedestrian, though to understand the difference in scale between the two blocks I took the final step of building 1/8" scale models. Built 40 feet deep into each block and constructed from foam core, chicken wire, dowels, and cardboard, the models communicate what the Nolli Maps and photo transects could only suggest.

The Northern Block's edges do not simply differ from the Southern's, they have been fundamentally transformed. The newer developments stand at nearly 140 feet tall, almost five times the height of an average alley house, and the fragmentation of the eastern edge compounds this disorientation, leaving the alley caught between scales that bear no relation to one another.

What the comparison between the Northern and Southern Block reveals is the impact that edge conditions can have on the interstitial space of an alley. The alley's original function, that of service corridor, home entrance, gathering space, persists where the edge conditions remain intact, as in the Southern Block. However, when those original edge conditions are changed, so too does the function of the alley. Beyond function, a pedestrian's ability to orient themselves within the context of the neighborhood is also lost.

These two blocks of S. Bethel St. are only an instance in a pattern that showed itself across the six miles of alley that were studied. This window of insight into the variations of edge conditions reveals an example of the power that designers have when interacting with interstitial space, especially when those spaces serve pedestrian functions and carry powerful human stories.

Through Nolli Maps, scaled models, and thorough field investigation, landscape architects can better understand how their sites interact with interstitial spaces, and the ways in which designing these spaces thoughtfully may preserve and unveil cultural, social, and human histories.