Since 1908, the contractors who poured Corvallis's concrete sidewalks have stamped their names and dates into the wet concrete. More than a hundred contractors have done this over more than a century, creating a distributed public record of who built the city's walkways and when. It's the kind of urban detail that rewards slow walking — once you start looking for the stamps, you start noticing the history embedded in the pavements underfoot.
The practice is unique to Corvallis (Atlas Obscura recognised it as one of the more unusual local traditions in Oregon) and creates a chain of evidence that lets you walk down a block and read the history of the street by looking at your feet. The oldest stamps are in the downtown core, particularly around the historical buildings near the courthouse.