This example displays the ten most populous countries as a pathetic bar chart with no axes, using React to render SVG rectangles. The data comes from the United Nations World Population Prospects 2019, loaded via the `d3.csv` function. A `scaleBand` positions each country vertically, while a `scaleLinear` maps population values to rectangle widths. The chart uses `d3.v5` and React hooks like `useState` and `useEffect` to fetch and store the data, showing a simple loading message until the CSV is ready.