This example shows a world map rendered with D3.js, using green countries that turn red on hover. The visualization demonstrates fundamental DOM manipulation and event handling through D3’s `select`, `data`, and `enter` methods, while `d3.geoPath` and `d3.geoNaturalEarth1` project the TopoJSON data from the world-atlas dataset. The SVG paths respond directly to CSS `:hover` styling, illustrating how inexpensive interactivity can be achieved with minimal JavaScript.