The pre-foundational stages of new cities are marked by several decisive elements that ultimately led to their genesis. The reason for their existence and where they materialize necessarily depend on decisions made by agents, institutions and specific political-economic-social circumstances that have guided each of these undertakings. In some cases, new cities have not only involved the destruction of local ecosystems (human and natural) but even their eventual disappearance, within a context whereby the human species has simply viewed them as being subsidiary (almost always superfluous) to pursuing its colonizing determinations. The aim of this article, which is the result of post-doctoral research, is to characterize new cities, those intentionally created and professionally designed, as infrastructural devices for territorial activation and urbanization. Rather than being the end-products of a political-spatial dynamic, could these cities be understood as intermediary cogwheels for productive and extractive activities? In the pursuit of an answer, attention has been focused on the cities founded in the central-south region of the Amazon (Brazil) and in the Sines region (Portugal) during the 1970s, all of which emerged from developmentalism, state authoritarianism, the dynamics of capitalization and accumulation and the expanded participation of private sectors. While maintaining the due proportions and scalar differences, the processes of occupation, colonization, infrastructure development, and exploitation of natural assets characterize both territories, including the predatory urban planning practices that are harmful to local ecosystems. Thus, these cities have become our exploratory field in this investigation, conducted through an historical perspective, underpinned by consultations with primary and secondary sources and on-site visits. With an understanding that “nothing comes from nothing”, this study qualifies each new city as a representation of the conditions that led to its birth and its strategic position in the recent capitalist system.