The human brain is a highly complex system, with different levels of spatial organisation. E.g., on a macroscopic level, the brain shows a highly variable folding pattern, while nerve cells on a microscopical level are arranged in layers and columns in a regionally specific way. Cytoarchitecture is a concept that itself encompasses different aspects of brain organization – the different cell types have distinct morphology, molecular, genetic and connectional fingerprints. Axons form complex networks at the level of microcircuits or large cognitive system. To capture the cellular and axonal architecture and to study the role of a specific brain region to function or behaviour requires to analyse the brain in 3D with microscopical resolution. Deep-learning offers new tools to 3D reconstruct images of histological sections at the microscopical scale, and convolutional neuronal networks support to automatize brain mapping. Considering the size of the brain with its nearly 86 billion nerve cells, HPC-based workflows play an increasing role for developing high-resolution brain models, to tame brain complexity. To develop such tools is key in the Human Brain Project. It is building a European research infrastructure for brain research, to collaborate towards a better understanding of the human brain.