This lecture celebrates the 20th anniversary of LaSUR, the Urban Sociology Laboratory at EPFL. The instructor discusses the laboratory's role in bridging urban sociology with architecture and engineering. They reflect on personal experiences, highlighting how LaSUR transformed their understanding of European sociology and facilitated interdisciplinary collaborations. The concept of 'ecotones' is introduced, representing the intersection of different ecosystems, which parallels LaSUR's position at the crossroads of social sciences, engineering, and architecture. The instructor emphasizes the laboratory's open approach to research and its importance as a platform for young researchers. The celebration aims to revisit past achievements and outline future aspirations for the next decade, focusing on the laboratory's commitment to interdisciplinary work and collaboration among architects, urban planners, engineers, and social scientists.