This example shows the global total COVID-19 deaths over time as a single black line chart, with a horizontal marker line at six million deaths. The data comes from the CSSE COVID-19 time series CSV, aggregated daily across all countries. Built with React and D3 v5, it uses `scaleTime`, `scaleLinear`, and `line` to map dates and death totals to SVG coordinates, while the marker line is drawn with a simple SVG `<line>` element at a fixed y-value.