This essay examines the convergence of the science-fiction motif of terraforming with current discussions of the Anthropocene. In the process, it outlines a vision of the city, not as the antithesis to nature or a biological wasteland but as itself a form of nature. This vision of the city as a natural system contrasts with conventional dystopian visions of future cities as scenarios of exploitation, crisis, and disaster. Science-fiction novelist, Kim Stanley Robinson's 2312 uses high-modernist literary strategies to create a narrative of cities and planets as humanly transformed but nonetheless natural environments. Harryette Mullen's minimalist volume of poetry Urban Tumbleweed echoes Robinson's urban vision and the narrative of flânerie by which he explores the newly natural streets of large metropolises. Mullen's account of Los Angeles converges with Robinson's landscape of Mercury in their effort to understand city and nature as elements of the same transformation processes. Both not only display the processes of terraforming that create nature in and out of cities, thus cities as part of nature, but also expose the processes that create and undo cultural and political communities at the same time. The result is a vision of urban communities in which varieties of humans and nonhumans make their presence felt and their voices heard—a more-than-human democracy that turns the idea of the Anthropocene away from its uniquely human focus.