This example displays a world map using a Mercator projection, rendering country boundaries as SVG paths from TopoJSON data. The visualization fetches the world-atlas dataset and uses `d3.geoPath` with a `geoMercator` projection to convert geographic coordinates into screen paths. Each country is appended to the SVG as a separate path element. The code relies on D3 v5 and the topojson library to parse and extract country features from the TopoJSON format.