This example shows a horizontal bar chart of the ten most populous countries, with populations displayed in billions using a custom tick format. The chart uses d3.scaleLinear and d3.scaleBand to map population values and country names, while d3.axisBottom and d3.axisLeft render the axes. Key customizations include removing domain lines, adding gridlines via tickSize, and appending an axis label. Data is loaded from a CSV file with d3.csv, and the visualization is rendered as SVG with D3 v5.