Wake flows – the fluid mechanical “debris” shed behind an aerodynamic body – are often characterized by unsteady, turbulent, low-momentum fluid. Usually these wakes are to be avoided, but in several situations the wake can exhibit an organized structure consisting of well-defined high energy vortices. Examples of these coherent, or structured, wakes include trailing vortex flows behind animals in flight or swimming fish as well as the vortices shed behind wings pitching to high angles of attack. In this talk I will illustrate several examples of structured wakes in both natural and engineered systems, drawing from several projects from our lab including measurements of enhanced renewable energy harvesting using arrays of oscillating flow turbines, and energy savings experienced by birds flying in small flocks.