This example visualizes the top five most populous countries from the UN World Population 2019 dataset as a horizontal bar chart. Each bar’s length encodes the estimated population for 2020, with tooltips showing the value in billions. Using React and D3 v7, the chart employs `scaleBand` for the categorical y-axis, `scaleLinear` for the numerical x-axis, and custom React components for axes. The SVG bars are rendered with `<rect>` elements, while axes use D3’s tick generation with SI formatting that converts billions to “B”.