This interactive family tree visualization in D3.js v3 displays hierarchical relationships among named individuals, with expandable and collapsible nodes. Clicking a node toggles its children, animating the tree’s layout with smooth transitions. The SVG-based chart uses `d3.layout.tree` for positioning and `d3.svg.diagonal` for curved links. Built with React, it renders circular nodes with labels and color-coded states, animating position changes via `transition` over 750 milliseconds.