Juicebox is a visualization tool for Hi-C contact maps and other contact map data, allowing users to zoom in and out interactively, similar to how users zoom in and out on a geographic map in Google Earth. It integrates technologies from the Integrative Genomics Viewer with methods specifically designed for 2D contact data. Juicebox enables users to explore Hi-C heatmaps, normalize maps, compare them to 1D tracks (e.g., gene tracks or ChIP-seq data) or 2D feature sets (e.g., loop and domain annotations). Multiple maps can be compared side by side, revealing conservation and variation across cell types and species. Users can create their own heatmaps to explore their experiments. Juicebox allows zooming into Hi-C maps to resolve increasingly small features, revealing chromosome territories, chromosomal rearrangements, and chromatin loops. At higher resolutions, chromatin loops are visible as bright peaks, and at 1-Kb resolution, the relationship between loops and point-source epigenetic tracks can be examined. Juicebox is available as a Java application and is open source under the MIT license. It can be used to explore data from over 15 Hi-C, 5C, and CHIA-PET publications. Juicebox helps researchers zoom inward to study chromatin architecture, enabling deeper insights into genome folding.Juicebox is a visualization tool for Hi-C contact maps and other contact map data, allowing users to zoom in and out interactively, similar to how users zoom in and out on a geographic map in Google Earth. It integrates technologies from the Integrative Genomics Viewer with methods specifically designed for 2D contact data. Juicebox enables users to explore Hi-C heatmaps, normalize maps, compare them to 1D tracks (e.g., gene tracks or ChIP-seq data) or 2D feature sets (e.g., loop and domain annotations). Multiple maps can be compared side by side, revealing conservation and variation across cell types and species. Users can create their own heatmaps to explore their experiments. Juicebox allows zooming into Hi-C maps to resolve increasingly small features, revealing chromosome territories, chromosomal rearrangements, and chromatin loops. At higher resolutions, chromatin loops are visible as bright peaks, and at 1-Kb resolution, the relationship between loops and point-source epigenetic tracks can be examined. Juicebox is available as a Java application and is open source under the MIT license. It can be used to explore data from over 15 Hi-C, 5C, and CHIA-PET publications. Juicebox helps researchers zoom inward to study chromatin architecture, enabling deeper insights into genome folding.