This article examines a series of projects and proposals concerned with sculptures built alongside highways. It aims to illuminate an understudied history of architectural sculpture in concrete (béton), taking us beyond the traditional canon or works. These sculptures are significant within the history I trace because they are not merely influenced by architecture, but actively engage architectural forms as part of their construction of a shared private–public space along the roadside. By analysing categories such as scale, shape, mass, proportion, technological principles and the materials of the work, alongside the public context, my broader research agenda is to trace the ways in which architecture figures within and against these sculptural works. The article also traces some of the history of how art along the highway was connected through the network of the International Sculpture Symposium. The ideas that were disseminated by the different International Sculpture Symposia were important to an increasing degree and for bringing art out of museums and into public space.