This bar chart displays the top ten countries by 2020 population, sourced from a UN population CSV loaded via `d3.csv`. The React app uses `useState` and `useEffect` to fetch and slice the data, then renders an SVG with `d3.scaleBand` for the categorical country axis and `d3.scaleLinear` for the population values. Gridlines and tick labels are generated with `xScale.ticks()`, while each bar is a `<rect>` positioned using the scales. The code includes a commented-out static circle example, indicating an early stage of the visualization project.