This bar chart displays the top 10 most populous countries using data from the United Nations World Population Prospects 2019. The chart uses SVG rendering within a React component, leveraging D3’s `scaleBand` for the categorical y-axis and `scaleLinear` for the population x-axis. Axes are drawn with custom React components (`AxisBottom`, `AxisLeft`), while `Marks` renders each bar with a tooltip. Population values are formatted with D3’s `format` function, converting large numbers to billions with a "B" suffix.