Living systems are complex – spatial transcriptomics allows us to understand not only what genes are expressed but also where that expression occurs, providing a key link between gene activity and biological function within cells and tissues. These images depict tissue sections of planarian flatworms, which are highly regenerative animals with the ability to regenerate all adult tissues, including the brain. Here, I utilized multiplexed error-robust fluorescence in situ hybridization, or MERFISH, to map the spatial expression of 282 genes across ~500,000 individual RNA molecules.