This interactive bar chart visualizes the population of 20 countries for the year 2010, sourced from a CSV file fetched via `d3.csv`. Built with React and D3 v5, it uses `d3.scaleBand` for the categorical y-axis and `d3.scaleLinear` for the numerical x-axis. The SVG rendering includes custom axis components, tooltips via `<title>` elements, and a tick format that converts large numbers to billions using `d3.format`.