A horizontal bar chart displays the top 10 most populous countries, using data from the United Nations World Population Prospects 2019. The chart presents population values formatted in billions, with country names on the y-axis and a labeled x-axis. Built with React and D3 v5, the visualization uses `scaleBand` and `scaleLinear` for positioning, and SVG `rect` elements from the `Marks` component to render bars with tooltips.