Discovered by Giuseppe Peano in 1890, Peano curves are one-dimensional curves that densely fill higher-dimensional space. A published 3-D map of the genome suggests that long stretches of DNA fold into Peano, curve-like structures. A team of researchers from Harvard University, the Broad Institute of Harvard and the Massachusetts Institute of Technology (MIT), the University of Massachusetts Medical School, and MIT deciphered the 3-D structure of the human genome, paving the way for new insights into genomic function and expanding our understanding of how cellular DNA folds at scales that dwarf the double helix. Credit: Leonid A. Mirny and Erez Lieberman-Aiden