This heat map visualizes global land temperatures from 1753 to 2015, with each cell representing a month-year combination colored by its deviation from a baseline of 8.66°C. The SVG rendering uses D3.js scales for axes and color mapping, fetching data from freeCodeCamp’s GitHub repository. Tooltips and a legend are implemented to show exact values on hover, while the color gradient divides temperature ranges into nine discrete categories via a custom `applyColor` function.