This visualization displays a horizontal bar chart comparing the 2020 populations of thirty countries. The bars are rendered as SVG rectangles, with length encoding population value. The code uses React with D3 v5, employing `d3.csv` to load data from a GitHub-hosted CSV file. Axes are built using `d3.scaleBand` and `d3.scaleLinear`, with a formatter converting values to billions. A tooltip showing the population value appears via an SVG `<title>` element on each bar.