This example shows a bar chart of total COVID-19 cases aggregated by country, using data from a WHO global dataset. It first displays the raw categorical bars with steelblue fills, then rotates the x-axis labels for readability. The visualization is built with D3 v7, using `d3.csv` to load the data, `d3.sum` for aggregation, and `d3.scaleBand` with `d3.scaleLinear` for positioning. An SVG container with explicit margins renders the axes via `d3.axisBottom` and `d3.axisLeft`, while a rotated y-axis label clarifies the metric.