This map visualizes Napoleon’s 1812 Russian campaign, showing the army’s advance and retreat as a flow line whose thickness encodes the surviving troop count. The path splits into three groups, with city labels marking locations, while a separate temperature chart plots the frigid retreat conditions. Built with D3 v7, the visualization renders SVG elements, using `d3.scaleLinear` for axes, `d3.line` for the temperature curve, and `d3.group` to organize the data by army group and direction. The `index.js` file parses embedded CSV data for troops, cities, and temperatures, with CSS styling for the tooltip and legend.