Basement membranes (BMs) are polymers of matrix proteins underlying epithelia and surrounding organs in all animals. BMs and Collagen IV, their main component, are actually the key evolutionary innovations allowing the existence of tissues and the evolution of complex body plans in the Metazoa. In my laboratory, we are trying to understand the biology of tissues and BMs using the fruit fly Drosophila melanogaster as a model organism, mostly through genetics and cell biology approaches. During my talk, I will present our findings regarding the secretion of Collagen IV, the hierarchy of assembly of BM components and the developmental roles of BMs in mechanically shaping tissues and regulating tissue growth. I will also discuss results from my laboratory showing that Collagen IV can mediate intercellular adhesion through a novel form of matrix organization that we call CIVICs (Collagen IV Intercellular Concentrations). Finally, I will present recent data on how microtubule organization ensures proper Collagen release by secreting cells.