This horizontal bar chart displays the top 20 countries by their 2010 population, sourced from a CSV file fetched via d3.csv. The React visualization uses d3.scaleBand for the categorical country axis and d3.scaleLinear for the population scale, rendering SVG rectangles with hover tooltips. Axes are built with custom React components, and the x-axis formats tick labels using d3.format to abbreviate large numbers into billions.