This example shows a basic bar chart of population data for ten countries, with each country represented by a rectangle. The visualization uses D3 v5 APIs including `select`, `csv`, `scaleLinear`, and `max` to load the data, parse the population values, and append SVG rectangles to the chart. The bars are styled with a steelblue fill via CSS, though the code currently sets a fixed width and height for all rectangles, so it does not yet scale the bars to reflect the data values.