This visualization displays the global cumulative death toll from COVID-19 over time as a single black line chart. It uses a React component with D3 v5 scales (`scaleTime`, `scaleLinear`) and a `line` generator to plot data from the JHU CSSE COVID-19 time series dataset. Dashed horizontal markers label key thresholds (10,000 to 2,000,000 deaths) via a custom `YMarkerLine` component, which draws SVG `<line>` elements and formatted text labels. The chart fills the browser window and updates when new data is loaded.