A world map uses semitransparent orange circles to show cumulative COVID-19 case counts by country on March 25, 2020. The visualization renders country boundaries as SVG paths via `d3.geoPath` with a `geoMercator` projection, and scales circle radii with `d3.scaleSqrt`. Data comes from a CSV of Johns Hopkins case counts, loaded with `d3.csv`. A range slider is present, but it does not currently change the displayed date.