Ferromagnetic nanostructures are considered to be the building blocks for the development of future spintronic devices 1 where cylindrical nanowires are interesting candidates, particularly as their domain wall propagation has been predicted to surpass the speed which is usually limited by the Walker breakdown in structures like flat nanostrips and thin films. 2 Understanding the fine structure of domain walls in ferromagnetic nanowires is therefore mandatory.Such difficult studies require a method that allows a quantitative magnetic mapping with nanometer spatial resolution, as well as a three-dimensional representation of magnetic domain walls for cylindrical nanowires. 3