A line chart tracks daily cumulative COVID-19 deaths worldwide, with a horizontal marker line fixed at 10,000 deaths. The React component uses `d3.scaleTime` and `d3.scaleLinear` to map dates and death totals, while `d3.line` generates the SVG path. Data comes from a JHU CSSE time-series CSV, aggregated by summing country-level deaths per day. The black stroke emphasizes the trend, and the marker line offers a fixed reference threshold.