Most of what we know about organogenesis comes from static studies of organ anatomy during embryogenesis. But tissue assembly is a dynamic process,involving many individual cell movements. To follow endothelial cell dynamics in vivo during vasculogenesis in quails, Rupp and co-workers used digital time-lapse scanning microscopy to track the movements of endothelial cells tagged with a surface marker (see p. 2887). They describe five types of endothelial cell motion during normal vasculogenesis:global tissue deformation; vascular drift, in which the entire vascular plexus migrates medially; structural rearrangements (such as vascular fusions);individual cell migrations; and cell process extensions. These different cell motions are subtly altered by an αvβ3 integrin inhibitor, leading the researchers to conclude that the previously reported wide-scale abrogation of vasculogenesis caused by inhibiting this integrin results from disrupting these specific cell movements. This technique will hopefully yield new insights into other morphological processes in development.