Historically, the territorial metabolism of human settlements developed as circular, creating a meaningful balanced link between the city and its surroundings. Nevertheless, the industrial revolution of the 19th century and the globalization of the 20th replaced the circle with extensive lines, crossing the hinterland territories around urban areas and abolishing the existing relationship. The presentation examines the 8000 years long history of the roman polis of Serdica (today Sofia) in its relation to the resourcefulness of the plain. Located on the road from Rome to Constantinople, Sofia’s formation and development are linked to two favorable geographical factors, which sustained its residents for centuries: the location of river Iskar’s bed and its multiple tributaries forming a fertile lower terrace suitable for agriculture; and the multiple thermal mineral water springs. During the industrialization period, this same flatness of the plain stimulated the construction of multiple railroads, leading to a network three times denser than in the rest of the country, and the development of some of the largest industrial sites and extraction mines in Bulgaria. Could these redundant monotechnic infrastructures become polytechnic- drivers for new circularization practices?