A bar chart displays the top 10 most populous countries, using United Nations World Population Prospects 2019 data from a CSV file. The code loads the data with `d3.csv`, scales the population values, and renders horizontal bars with `d3.scaleLinear`, `scaleBand`, `axisLeft`, and `axisBottom`. Tick labels are formatted with `format('.3s')`, and the chart includes axis labels and a title. The visualization is drawn as SVG elements within a 960×500 viewport, with bars styled via CSS.