This example shows a world map where countries are colored according to sample population data using a sequential blue color scale. Hovering over a country highlights it in orange, and moving the cursor away restores its original fill. The map is rendered as SVG with the `d3.geoNaturalEarth1` projection and `d3.geoPath` using TopoJSON data from world-atlas, while population values are mapped through `d3.scaleSequential` and `d3.interpolateBlues`.