This example shows a horizontal bar chart of populations for twenty countries in 2010, using a bar’s length to encode the population value for each country. The visualization is built with React and D3 v5, using `scaleBand` for the categorical y-axis and `scaleLinear` for the numeric x-axis. Custom React components (`AxisBottom`, `AxisLeft`, `Marks`) render SVG ticks and rectangles, with a tooltip showing the formatted population value on hover. Data is loaded as CSV with `d3.csv` from a GitHub repository and formatted using `d3.format`.