Let's make a map with D3.js!
This example demonstrates how to create an interactive world map using D3.js v5 with TopoJSON data from the world-atlas package. The map renders countries as SVG paths using the `d3.geoNaturalEarth1` projection and `d3.geoPath` generator, with a blue sphere background. Country shapes are filled green and turn red on hover, while each path includes a title element displaying "hello". The code loads geographic data asynchronously via `d3.json` and converts TopoJSON features using the `feature` function from the topojson library.