Recent progress in the design and application of artificial cellular microenvironments and nanoenvironments has revealed the extraordinary ability of cells to adjust their cytoskeletal organization, and hence their shape and motility, to minute changes in their immediate surroundings. Integrin-based adhesion complexes, which are tightly associated with the actin cytoskeleton, comprise the cellular machinery that recognizes not only the biochemical diversity of the extracellular neighbourhood, but also its physical and topographical characteristics, such as pliability, dimensionality and ligand spacing. Here, we discuss the mechanisms of such environmental sensing, based on the finely tuned crosstalk between the assembly of one type of integrin-based adhesion complex, namely focal adhesions, and the forces that are at work in the associated cytoskeletal network owing to actin polymerization and actomyosin contraction.