This example shows a choropleth map of world countries colored by economic grouping, with interactive selection: clicking a country dims all others and highlights the chosen region, and clicking again clears the selection. A color legend filters the map to a single category. The visualization uses D3 v5 with `geoNaturalEarth1` projection and `geoPath` for rendering SVG paths, plus `zoom` for panning. Data comes from TopoJSON and TSV files via the world-atlas package, with colors assigned by `scaleOrdinal`.