A choropleth map shows the global prevalence of HIV/AIDS among adults aged 15-49 for the year 2017, using a yellow-to-red sequential color scale where darker shades indicate higher infection rates. Countries with missing data appear in light gray. The visualization is built with React and D3 v7, using `geoNaturalEarth1` and `geoPath` for map projection, `geoGraticule` for grid lines, and TopoJSON world atlas data. The choropleth applies a `scaleSequential` with `interpolateYlOrRd` to color each country polygon.