This visualization shows a hierarchical force-directed graph with interactive drill-up and drill-down capabilities, displaying both a high-level community structure and detailed node-level views. The graph renders in SVG and uses D3.js's force simulation APIs, including `forceSimulation`, `forceLink`, `forceManyBody`, and `forceCenter`, along with a zoom behavior. Users can navigate between hierarchy levels by clicking on community nodes to expand them into their constituent node networks, or drill back up to the parent level. The data comes from the Les Misérables character network and an email communication dataset (email-Eu-core), parsed from edge-list text files.