This example presents an interactive choropleth map of the world, where each country is colored according to its economic classification. Users can click on any country to highlight it, dimming all others, and click again to deselect. The map uses D3's `geoPath` and `geoNaturalEarth1` projection, with `scaleOrdinal` and `schemeSpectral` for the color scale. A separate legend allows filtering by economy value, and the zoom feature (`zoom()`) is included. Data comes from the `world-atlas` package, loaded with `tsv` and `json`.