A horizontal bar chart displays the top 10 most populous countries using data from a CSV file. It maps population to bar width with a linear scale and country names to bar height using a band scale. The axes are customized with d3.axisBottom and d3.axisLeft; tick lines are removed, grid lines are added, and population values are formatted with d3.format to abbreviate billions as "B". The visualization is rendered as SVG with D3 v6.