This visualization displays a horizontal bar chart comparing the populations of the top 20 countries in 2010, with countries listed on the y-axis and population values on the x-axis. The chart uses green bars with blue axis tick marks and includes a formatted axis label for population. Built with React and D3 v5, the code implements custom SVG components (AxisBottom, AxisLeft, Marks) using d3.scaleBand and d3.scaleLinear. Population data is loaded via d3.csv from a GitHub-hosted dataset, with values formatted using d3.format to abbreviate large numbers (e.g., "B" for billions).