Embedded into the sidewalk outside of the Michigan Avenue Fannie May store are dozens of small rectangular metal plates arranged in a curious pattern. A bit of exploration reveals that the plates span the intersection and mark the original footprint of Chicago's Fort Dearborn, which was torn down in 1857.  

The city installed the plates as a kind of memorial to its lost military outpost, but the significance of their placement goes beyond the commemoration of the fort. The use of the sidewalk as a memorial space is just one of many functions sidewalks have served in urban areas. 

Their most obvious function is a pedestrian one: they provide a means by which city walkers can travel by foot from one place to another in relative safety. But sidewalks have also been home to urban necessities like street addresses, laid out in front of buildings in a variety of designs, and, in an earlier era, iron rings meant to secure horse reins—the 19thand early-20thcentury equivalent of a parking spot. Recognizing the opportunities presented by sidewalk traffic, peddlers selling food, goods, and services set up temporary shop on any walkway stable enough to support foot traffic. And anyone who's seen a pair of hand or paw prints immortalized in a section of sidewalk knows that, given the opportunity, people will leave unsanctioned graffiti in any unattended plot of wet cement. 

Over time, city and state officials have passed regulations to regulate sidewalk use and repair. One of the more visible manifestations of these policies are the thousands of contractor stamps embedded into Chicago's sidewalks. For over one hundred years, Illinois law has required contractors to mark the sidewalks they construct with nameplates announcing their company name and the year. This requirement has resulted in the creation of unique sidewalk stamps dating back more than a century. Both then and now, the mandatory stamps have presented opportunities for paving companies to advertise their services, which has contributed to the wide variety of stamp designs.  

So the next time you stop at a site, be sure to look down. Sidewalks can provide new clues to the urban past, and you never know what you might find.  

Chrucky, Serhii. "Sidewalk Stamps." http://forgottenchicago.com/articles/sidewalk-stamps/. Accessed August 2016.  

Hornstein, Leon, Frank Derby, and Ruth Nelson. The Chicago Municipal Code of 1922. Chicago: Chicago City Council, 1922.  

Text and photograph by Hope Shannon, Loyola University Chicago