This chart shows the global cumulative COVID-19 death toll over time, with a horizontal marker line at the one-million-death threshold. The line chart uses d3.scaleTime for dates, d3.scaleLinear for deaths, and d3.line to generate the path. A horizontal `line` element is positioned using the y-scale’s value for 1,000,000. Data comes from the CSSE COVID-19 time series CSV, aggregated daily across all countries, and renders as an SVG in a React component.