This bar chart visualizes the population of the top 10 most populous countries using 2018 estimates from the United Nations World Population Prospects 2017. It demonstrates how to customize D3 axes with custom tick formatting using `d3.format`, removing axis domains, and adding axis labels. The code uses `d3.scaleLinear` for the x-axis, `d3.scaleBand` for the y-axis, and renders the chart as SVG.