Combining expansion and the lattice light sheet Optical and electron microscopy have made tremendous inroads into understanding the complexity of the brain. Gao et al. introduce an approach for high-resolution tracing of neurons, their subassemblies, and their molecular constituents over large volumes. They applied their method, which combines expansion microscopy and lattice light-sheet microscopy, to the mouse cortical column and the entire Drosophila brain. The approach can be performed at speeds that should enable high-throughput comparative studies of neural development, circuit stereotypy, and structural correlations to neural activity or behavior. Science , this issue p. eaau8302