This interactive bar chart displays the top 10 most populous countries in 2020, using data from the United Nations World Population Prospects 2019. Built with React and D3 v5, it renders an SVG with horizontal bars, axes, and tooltips. The y-axis uses a band scale for categorical country names, while the x-axis applies a linear scale with SI-formatted tick labels (e.g., “1.4B”). The code splits visualization logic across separate components for axes and marks, loading CSV data via the `useData` hook and `d3.csv`.