This D3.js visualization shows the progression of COVID-19 cases, deaths, and recoveries over time for a selected country. Users choose a status metric and country via dropdown menus, and the chart displays a smooth line chart of that metric against observation dates. The code uses D3 v5 methods like `scaleTime`, `scaleLinear`, `axisBottom`, `axisLeft`, and `line` with `curveBasis` to render the SVG. Data is loaded from a CSV file and aggregated by country and day using `nest` and a custom `groupByDay` function.