This line chart displays global cumulative COVID-19 deaths over time from the Johns Hopkins dataset, with a horizontal marker line at the one-million-death threshold. The React component uses D3 v6 functions `scaleTime`, `scaleLinear`, `extent`, `max`, and `line` to construct an SVG path. Data loading relies on `csv` and `timeParse` to transform daily country-level death counts into aggregated totals. The marker line is drawn as an SVG `<line>` element, while the path is unstyled except for a black stroke defined in the page’s CSS.