Historical Organization
Saint Petersburg Academy of Sciences
Euler showed that the requested walk was impossible by reducing the city to land regions and connecting bridges.
Ignoring distances and shapes allowed Euler to focus on connections, a foundational move toward graph theory and topology.
The four land areas each had an odd number of incident bridges, preventing a trail that used each bridge exactly once.
Euler's publication is a conventional origin point, while continuous-line traditions in Africa and Oceania show other culturally embedded studies of paths and networks.