This example shows an interactive world map where clicking a country turns it green while all other countries remain red, displaying a selected-country highlighting behavior. The visualization loads geographic data from the world-atlas TopoJSON dataset and country names from a corresponding TSV file, then renders the map using d3.geoPath with a d3.geoNaturalEarth1 projection. Click events trigger a re-render that updates fill colors based on the selected country’s ID. The code uses d3.json, d3.tsv, and d3.select to manage data loading and SVG elements.