This bar chart displays the top 10 most populous countries in 2020, with horizontal bars ranked by population size. Built with React and D3 v5, it uses `scaleBand` for the categorical y-axis and `scaleLinear` for the quantitative x-axis. The SVG rendering includes custom `AxisBottom` and `AxisLeft` components, with formatted tick labels converting gigabyte units to billions. Data comes from the United Nations World Population Prospects 2019, loaded asynchronously via `d3.csv`, and each bar includes a native SVG `title` tooltip showing the exact population value.