This bar chart displays total online sales revenue by year for a customer dataset, with a fixed y-axis scale of 0 to 90 and red bars representing revenue values. The visualization uses D3.js v4 to parse CSV data from a GitHub repository, scale the categorical year values on the x-axis via `d3.scaleBand`, and map revenue to a linear scale on the y-axis. SVG rectangles are drawn for each bar, while `d3.axisBottom` and `d3.axisLeft` generate the labeled axes, with rotated x-axis text for readability.