This bar chart visualizes the top 20 countries by population in 2010. It uses a horizontal layout, with country names on the y-axis and population on the x-axis, formatted in billions. The visualization is built with React and D3 v5, employing `scaleBand` and `scaleLinear` for axes, and SVG rectangles for the bars. Data is loaded asynchronously from a CSV file using D3's `csv` function, and a tooltip displays the exact population value for each bar.