This choropleth world map visualizes population data for nine countries, using darker blue shades to represent higher populations. It loads country boundaries from the world-atlas TopoJSON dataset, converts them to GeoJSON with topojson-client’s feature function, and renders them as SVG paths via d3.geoPath with a Natural Earth projection. A d3.scaleLinear color scale maps population values to a light-to-dark blue range, and each country includes an SVG title tooltip showing the name and population in millions.