This example shows a choropleth world map using Natural Earth projection to display numeric values for selected countries, with a sequential YlGnBu color scale indicating magnitude. Tooltips reveal ISO numeric country IDs and their values on hover. It loads world-atlas TopoJSON data, renders via SVG, and employs d3.geoNaturalEarth1, d3.geoPath, d3.scaleSequential, and d3.csvParse. A gradient legend with a linear axis communicates the value range at the bottom.