The brain of higher primates comprises nearly 1014 nerve cells with delicate and complex connections among them. To fully understand how the brain functions, it is essential to have a high-resolution map showing how the nerve cells are organized and connected within the brain. BI Guoqiang and LAU Pakming at the CAS University of Science and Technology of China (USTC) and the CAS Shenzhen Institute of Advanced Technology and their collaborators have now realized 3D mapping of the entire brain of a macaque monkey at a resolution of 1×1×2.5 microns based on high-throughput 3D fluorescence imaging technique VISoR, combined with serial sectioning and clearing, 3D microscopy, semiautomated reconstruction and tracing (SMART).