This example renders a simple map of Europe using D3’s `d3.geoMercator` projection and `d3.geoPath` to convert GeoJSON features into SVG paths. The code fetches geographic data from a remote GeoJSON URL, assigns each feature a white fill and grey stroke, and displays the map in a 600×500 SVG container. It integrates React 16.9 and D3 v5, with the map drawn imperatively by selecting the body and appending SVG elements rather than using React’s virtual DOM.