A bar graph displays population estimates for four countries, sourced from a local CSV and rendered as SVG. The visualization maps population to horizontal bar length and country names to vertical positions, using a linear scale and a band scale. It is built with D3 v6, employing functions like `select`, `csv`, `scaleLinear`, `scaleBand`, and the `axisLeft` and `axisBottom` helpers. The chart includes styled tick marks, a title, and an axis label, with the population axis formatted in billions.