This zoomable treemap visualizes global cause-of-death data, using a CSV dataset that records death counts across four nested levels: broad cause, subcause, and specific disease. Built with D3 v2 and rendered as SVG, the treemap encodes hierarchy and quantity through rectangular area and color. Users can click to zoom between levels, and the visualization animates smoothly during transitions. The root node aggregates over 800 million deaths, with branches for Disease, Non-communicable, health complications, and Cancer, allowing exploration from global causes down to individual conditions. The example uses a custom data-reshaping function to transform the CSV into the nested structure the treemap layout requires, and includes CSS styling for interactive hover states and text labels.