Ecology is a multi-faceted term intertwined in art, architecture and urbanism. This article investigates an ontological history of ecology in art and architecture since the postwar period in the United States through the lens of selected urban and land works by the American modernist artists, architects and urbanists. The rapid commodification of the built environment surreptitiously influenced subliminal perception of modernist artists who visualized and introduced a new way of engagement with the land in the 1950s and 1960s. Inherently, the discourse posited entangled relations around the land as it is originally of the indigenous. The attempts to decenter itself from nature-culture dualism of settler colonialism developed ever since in form of social engagement, activism insofar in practices in art and architecture. Entropy is a measure of disorder explaining the irreversible process of nature from the second law of thermodynamics. Thermal changes in atmosphere, the sign of anthropocene was foreseen by Robert Smithson (1938-1973) using the term, entropy in contemporary art in his sequential writings deploying its attribute approaching the sameness during an era he termed, Ultra-Modernism. “In a rather round-about way, many of the artists have provided a visible analog for the Second Law of Thermodynamics, which extrapolates the range of entropy by telling us energy is more easily lost than obtained, and that in the ultimate future the whole universe will burn out and be transformed into an all-encompassing sameness.” Robert Smithson, “Entropy and the New Monuments,” Artforum, June 1966. The ecology of equivocation, sustainability carries remnants seeking scientific solutions reducing entropy, carbon-dioxide in the atmosphere. This article includes visualized alternative propositions of ecological design re-accessing land artworks. It includes the imminent future scenarios in coastal cities inundated with rising sea water, crystallized relics of monuments covered with debris of industrial wastes and seeks out localizing solutions with recycled or biodegradable materials, and from the ecological knowledge of Haudenosaunee, the indigenous peoples of the Northeastern Woodlands. And it questions how to engage with the public in digital era by interplaying foreground-background ambiguously.