A D3.js visualization displays a world map using a natural Earth projection, with countries rendered as SVG paths colored in bright green against a dark sea. Hovering a country turns it red and reveals its name via a tooltip. The map is built with `d3.geoPath`, `d3.geoNaturalEarth1`, and `d3.zoom` for interactive panning and zooming, while `d3.tsv` and `d3.json` load country names and geometries. A `topojson` feature layer draws each country, and CSS handles hover styling.