A horizontal bar chart displays the top 10 most populous countries from the United Nations World Population Prospects 2019 dataset, with population values formatted in billions. The visualization uses React with D3 v5, leveraging `d3.scaleBand` for the y-axis country categories and `d3.scaleLinear` for the x-axis population scale. Custom Axis components render SVG ticks and labels, while each bar includes a native SVG `<title>` tooltip element.