This example displays a world map choropleth of GDP data, with each country colored according to its economic value. It uses D3 v7 and TopoJSON to load world geography, projecting the map with the `d3.geoNaturalEarth1` projection and rendering countries as SVG paths via `d3.geoPath`. GDP values are fetched from a CSV file, matched to countries through flexible column-name heuristics, and visualized with a color scale. A hover tooltip provides country-specific details, while the map includes a legend for interpreting the color encoding.