Abstract: A comprehensive description of how neurons and entire brain regions are interconnected is fundamental for a mechanistic understanding of brain function and dysfunction. Neuroimaging has shaped the way to approaching the human brain’s connectivity at the macroscale on the basis of diffusion magnetic resonance imaging and tractography. At the same time, polarization, fluorescence, and electron microscopy became available, which pushed spatial resolution and sensitivity to the axonal or even to the synaptic level. However, such microscopic imaging techniques are typically restricted to small tissue samples as compared to an entire human brain, and they often require their own tissue preparation protocols inhibiting correlative, i.e. true multi-modal, imaging of the same samples. In my presentation, I will address the challenges of correlative imaging, the handling and the analysis of the acquired massive data sets, and the need for interoperable brain atlases for sharing well labeled, aligned, and curated neuroimaging data across scales.