This example visualizes the top 10 most populous countries as a horizontal bar chart, using data from the United Nations World Population Prospects 2019. It shows population values for each country in billions, with a formatted x-axis and a "Population" axis label. The chart is built with React and SVG, using d3.scaleBand for the categorical y-axis and d3.scaleLinear for the quantitative x-axis. The code demonstrates custom axes and marks components, with a tooltip displaying the formatted population value.