The momentum exchange mechanisms in a turbulent BL flow are of manifold temporal and spatial scales and governed by the organization of self-sustaining coherent flow structures driven by entrained high momentum fluid. Generic flow structures such as hairpin-like vortices and spanwise alternating wall bounded low- and high-speed streaks have been observed and extensively analyzed with both experimental and numerical methods, e.g. by means of PIV or DNS. In many studies the role of these structures for the wall normal and spanwise fluid exchange has been highlighted mostly within an Eulerian reference frame. But for a full understanding of the momentum exchange in turbulent wall flows a step towards a spatially resolved Lagrangian frame of reference would be advantageous. In order to achieve these ambitious goals a cooperation of TU Delft, LaVision and DLR planned and performed a Time Resolved Tomographic PIV experiment in a water tunnel at TU Delft. The data achieved from the present application of time-resolved tomographic PIV to a flat plate turbulent BL flow at Re ~ 2460 enables for the first time a topological investigation of the flow structures and related particle motions within a temporally and spatially highly resolved Lagrangian and Eulerian reference frame. In Figure 2 and in the animation an instantaneous 3D-3C velocity vector volume out of a 1 kHz time series is shown with selected velocity vector planes and 3D-iso-surfaces of swirl strength indicating the presence of vortices. In Figure 3 a zoom into a region with several particle trajectories is given representing the motion and acceleration of single fluid elements in a Lagrangian reference frame.