This interactive D3.js tree diagram displays a manually defined family hierarchy, with clickable nodes that collapse or expand their child branches. The visualization uses `d3.layout.tree` to compute node positions and `d3.svg.diagonal` for the connecting links, with smooth transitions between layout states. Node circles are colored red by default or lightsteelblue when collapsed, and text labels show names. The SVG rendering includes animated enter, update, and exit transitions driven by click events that toggle a node’s `children` and `_children` properties. The code loads D3 v3.5.17 from a CDN.