It is becoming clear that bacteria exist primarily as members of surface-adhered social communities, called biofilms, rather than as free-living individuals. These communities are encased in an extracellular matrix that provides protection from harsh environmental conditions, predation, enables resource sharing, and facilitates intercellular communication. Depending on the local conditions bacteria will transition between these two states and this interplay is fundamental to the ecology and biology of bacteria. The biofilm lifestyle colors all aspects of bacterial interactions with their environment whether attached to a rock in a stream, as an aggregate in activated sludge, or in an infection. To begin understanding biofilm development we visualize the initial encounter bacteria have with surfaces. Here, bacteria undergo a fundamental change in lifestyle, becoming surface-bound. We use cell tracking to link surface motility to surface exploration and colonization. As biofilms mature, growing three-dimensional, we utilize laser scanning confocal microscopy as well as label free imaging techniques to visualize phenotypic changes that occur within biofilms over time and space.