Urban ecotourism and urban rewilding may form a sustainable transition path for both tourism and urban wilderness. In an explorative case study, we analyse this option by reconstructing the history of an extensive urban wasteland formerly used as military shooting range and dumpsite and converted to a Nature Park in 2015. The transformation of this urban wasteland has a long history which is shaped by changes in society, technologies, and consequently in ecologies during different periods reflecting prevailing paradigms of nature perceptions over time. We seek to provide a theoretical frame using the social-ecological-technological systems (SETs) framework and transition theory to describe the transformations of the site from its pre-wasteland stage to rewilding and recreation and lately niche development of urban ecotourism. Results reveal that Nature Park Amager is an excellent case illustrating the transformation of an urban wasteland into a nature park providing recreational experiences, interpretative facilities, and guided ecotourism tours for tourists.