The visualization displays average annual temperatures by country on a world map, with a blue-to-red sequential color scale representing cold to hot climates. Unmapped countries appear gray. The map uses D3 v7 and TopoJSON to render geographic features via `d3.geoPath` with a natural Earth projection. A hardcoded dataset supplies temperature values for twelve countries, while hover tooltips reveal exact temperatures. The SVG includes a gradient legend with an axis, showing the temperature scale from -10°C to 30°C.