This line chart displays the global cumulative death toll from COVID-19 over time, using data from the Johns Hopkins Coronavirus Dataset. A horizontal marker line at 10,000 deaths highlights the threshold, with a labeled “10,000” text at the left edge. The visualization is built with React and D3 v5, using `d3.scaleTime`, `d3.scaleLinear`, and `d3.line` to generate the SVG path and axes. The marker line is drawn as a separate SVG `<line>` element, with the y-coordinate computed via the linear scale.