This example demonstrates how to create a world map with D3.js, displaying country boundaries as light green polygons on a dark blue background with a curved sphere outline. The visualization uses the `geoMercator` projection and `geoPath` to render geographic features as SVG paths. It loads world country data as TopoJSON from the world-atlas package, converts it to GeoJSON using the `feature` function from TopoJSON, and binds the resulting features to path elements. The map is static with no interaction or animation.