This visualization displays monthly global land-surface temperature anomalies from 1753 to 2015, using a base temperature of 8.66°C. A heatmap grid shows each month-year combination as a colored cell, with colors ranging from deep red (cold) to dark blue (warm). The D3.js code fetches JSON data from a FreeCodeCamp repository, scales the temperature values linearly, and renders an SVG with axes for years and months. d3.scaleTime, d3.scaleLinear, d3.axisBottom, and d3.axisLeft handle the scales and axes, while a separate legend shows the color scale.