This bar chart shows the population of the top 10 most populous countries, using 2019 estimates from the United Nations World Population Prospects. The visualization customizes both axes: the y-axis uses a band scale for country names, while the x-axis uses a linear scale with tick labels formatted in billions. The chart is rendered as an SVG using d3.scaleLinear, d3.scaleBand, d3.axisLeft, and d3.axisBottom, with grid lines and axis labels styled via CSS.