This example visualizes the top 10 most populous countries as a horizontal bar chart using React state management and D3 scales. The code loads the United Nations World Population Prospects 2019 dataset via `d3.csv`, then uses `scaleBand` and `scaleLinear` to map country names and population values to SVG rectangles. Hand-rolled axis ticks are generated with `xScale.ticks()`, and the visualization renders through ReactDOM, with SVG elements created directly in JSX rather than using `d3.axis`.