Ludwig Prandtl, who is considered to be the father of modern aerodynamics, made a number of films for demonstration and illustration purposes in the 1920s and 1930s, while he was at the Kaiser Wilhelm Institute for Fluid Mechanics in Göttingen, or, as it is now known, the Max Planck Institute for Dynamics and Self-Organization. In order to visualise fluid flow, Prandtl introduced small aluminium particles onto the water surface in the test channels. DLR researchers Christian Willert (Cologne) and Jürgen Kompenhans (Göttingen) tracked the movement of these particles using modern computer-based Particle Image Velocimetry (PIV) techniques. "We were able to determine the strengths and speeds of the vortices and visualise them using false colours," explains Kompenhans. Prandtl had not been able to do this. This treatment of the historical material clearly demonstrates the progress made in flow visualisation, from the early, simple presentation to a quantitative measurement method. Willert and Kompenhans received the Best Movie Award at the 14th International Symposium on Flow Visualization in Daegu, South Korea, for their contribution, PIV Analysis of Ludwig Prandtl's Historic Flow Visualization Films.