This example shows a basic bar chart of country populations, with each of ten countries represented as a rectangle. The chart initially renders all bars at a fixed width and height, though the data is loaded and parsed. The visualization uses D3 v6, specifically the `select` and `csv` methods, to load population data from a CSV file and append SVG `rect` elements. The SVG canvas is set to 960 by 500 pixels, and the chart is rendered entirely with SVG elements in the browser.