This example visualizes the hierarchy of ArcGIS-supported point-of-interest categories, with roughly 300 child categories grouped under 10 major parent categories. The tree is laid out horizontally using `d3.tree()` and `d3.hierarchy()`, with nodes positioned by size and links drawn via `d3.linkHorizontal()`. The SVG rendering is zoomable and pannable through `d3.zoom()`, and labels are angled at each leaf for readability. Data is loaded from a CSV file using `d3.csv`.