This bar chart visualizes the top five countries by population in 2015, using a dataset from a GitHub-hosted CSV file. The chart reads the data with the D3.js `csv` function and renders bars through the Vega-Lite API, a JavaScript wrapper for Vega-Lite specifications. It encodes country values on the x-axis and population on the y-axis, with tooltips displaying exact population figures. The visualization is configured with custom styling, including larger fonts and a dark color scheme, and uses the Vega and Vega-Lite libraries alongside the Vega Tooltip handler for interactive hovering.