A horizontal bar chart displays the top 10 most populous countries, with population values on the x-axis and country names on the y-axis. Built with D3 v5, it uses `d3.csv` to load the data, `d3.scaleLinear` and `d3.scaleBand` for scaling, and `d3.axisBottom` with a custom tick formatter that abbreviates large numbers to billions. The chart includes a title, axis label, and a steelblue fill for the bars.