A bar chart displays the top 10 most populous countries in 2020, using horizontal bars sorted by population. The visualization is built with React components and D3 scales (`scaleBand`, `scaleLinear`), rendering SVG rectangles for marks and custom axis components. D3’s `csv` loader fetches United Nations World Population Prospects 2019 data, with population formatted in billions. Tooltips show exact values via SVG `<title>` elements, while axes and labels are styled with CSS.