At low homologous temperatures, metallic glasses (MGs) admit limited plasticity via strain localization by so-called shear bands. Shear-bands are spatially confined to the nanometer scale, are active at very short time-scales, and leave only a faint signature of structural damage relative to the surrounding matrix. For decades, research has focused on revealing fundamental properties of shear bands, with the goal of identifying properties that may help us to design more ductile MG-alloys. In this talk, we discuss how fundamental properties of shear bands are linked to the macroscopic appearance of plastic flow. We will address the spatial signature of a shear bands and show that it is much more complex than the nano-scale core. Finally, our talk will cover the structural evolution of shear bands with plastic stain, which we believe represents one of the main unsolved questions in the area of shear banding in MGs.