This example shows a bar graph of country populations from a CSV file, displaying each nation’s population as a blue vertical bar. It reads the data using `d3.csv` from the D3 v7 library, then renders the SVG chart with `d3.select`, `d3.scaleBand` for the x-axis, and `d3.scaleLinear` for the y-axis, with bars drawn via `svg.append('g').selectAll('rect').data(data).join('rect')`.