On March 1, 1986, 1,200 activists set out from Los Angeles on a walk across the United States to call for an end to nuclear weapons. Within two weeks, a few hundred remained. They reorganized as the Great Peace March for Global Nuclear Disarmament and successfully completed the nine-month, 3,325-mile walk to Washington, D.C. Two central questions guide this work: What is the relationship between long-distance walking and the politics of social movements? To what extent does “endurance” shape meanings of the March’s related but twin goals: the building of a collective, or “prefigurative” community, and a mass movement capable of attaining media coverage and achieving concrete, or “strategic” political outcomes? This study utilizes historical analysis, semi-structured interviews, and discourse analysis of print news media to apprehend different perspectives on long-distance walks and the Great Peace March. This project provides a multilayered account of the historical and cultural roots of long-distance walks for sociopolitical change, the March’s origins and organization, marchers’ understandings of their participation, and media representations of the March. It also examines Jamie Schultz’s categorization of “physical activism” in combination with “prefigurative politics,” of which Wini Breines claims the central task is to create and sustain within the live practice of the movement, relationships and political forms that ‘prefigured’ and embodied the desired society. The result is a more nuanced understanding of the ways physicality and endurance constitute a significant aspect of participation in social movements. This dissertation coins the term “endurance activism” as the articulation of endurance physical feats with political activism. The Great Peace March illustrates how social movement participants undertook endurance actions to communicate arduous and strenuous work for the cause. This project finds that endurance, physically, but also symbolically and metaphorically signifies particular meanings of movement for social movements such as persistence, focus, and determination to stretch limits and push boundaries. The marchers sought to accomplish a difficult physical challenge and maintain the solidarity of their community to analogize the coming into existence of their campaign’s equally extraordinary vision for denuclearization. The marchers experienced and communicated endurance to stress their movement as an act that has no end, and to solidify perceptions of themselves as lifelong activists. Their emphasis on endurance highlights the importance of the means of lasting work for social and political change that are valued in and of themselves. This study finds that collective effort and striving are crucial qualities that build solidarity in social movements, while also signaling the necessity of ongoing work for the cause and the forging of another way forward.