This interactive tree diagram displays a family hierarchy loaded from a JSON file, with nodes labeled by names and connected by curved links. Users can click any node to collapse or expand its subtree, with smooth 1.1-second transitions animating nodes and links to new positions. The visualization uses D3.js v3’s `d3.layout.tree` for layout and `d3.svg.diagonal` for link paths, rendered as SVG with green-bordered circles and bold text labels. Node expansion state is managed by toggling between `children` and `_children` arrays.