Human brains have a uniquely large and functionally complex neocortex. To understand the features of cortical development that are unique to humans, James Noonan and colleagues mapped active promoters and enhancers during human, rhesus macaque and mouse corticogenesis (Science 347, 1155–1159, 2015). The authors profiled H3K27ac and H3K4me2 histone marks in cortical tissues at multiple homologous stages of corticogenesis to map active promoters and enhancers. They identified 8,996 enhancers and 2,855 promoters that had an increase in H3K27ac or H3K4me2 levels in human tissues compared to rhesus macaque and mouse tissues. Using available corticogenesis expression data, they generated a network model of cortical development and identified 96 sets of genes with highly correlated expression (modules). They integrated the lists of enhancers and promoters with human increases in H3K27ac or H3K4me2 signals and identified 17 modules that were enriched for these signals. These modules include genes associated with cortical development, neuronal progenitor proliferation, the extracellular matrix, and TGF-β and FGF signaling.