This interactive collapsible tree visualizes hierarchical data from a Santander bank dataset, rendered as an animated SVG using D3.js. It adapts the classic Reingold–Tilford tree layout: nodes are circles, links are curved paths, and clicking a node expands or collapses its children with smooth transitions. The dataset, stored in a JSON structure, groups items under category names like "analytics" and "physics," with leaf nodes sized by a numeric value. The visualization supports progressive disclosure, letting viewers explore the hierarchy by toggling branches while maintaining a clear left-to-right layout.