This interactive bar chart displays the top 10 most populous countries for 2020, using data from the United Nations World Population Prospects 2019. Horizontal bars are ordered by country name, with population values formatted in billions along the x-axis. Built with React and D3 v5, the visualization uses `scaleBand` for the categorical y-axis, `scaleLinear` for the numeric x-axis, and SVG `rect` elements to render each bar. Hovering over a bar reveals a tooltip with the formatted population value.