This bar chart displays the population of the top 10 most populous countries using 2018 estimates from the United Nations World Population Prospects 2017. It shows how D3 axes can be customized through tick formatting, tick size, and removing axis domains or tick lines. The code uses `d3.csv`, `d3.scaleLinear`, `d3.scaleBand`, `d3.axisLeft`, and `d3.axisBottom` to render the SVG. Population values are multiplied by 1000, and tick labels are formatted with `.2s` while replacing 'G' with 'B'.