This example visualizes world countries on a natural Earth projection, with each country colored light green and the ocean sphere in dark blue. Hovering highlights a country in red. The map is rendered in SVG using `d3.geoPath` with `d3.geoNaturalEarth1`, and country boundaries come from TopoJSON data loaded from the world-atlas package. Country names are joined via TSV data, and tooltips display them on hover.