A multi-line chart displays a week of temperature readings across multiple cities, with time on the x-axis and temperature on the y-axis. The visualization uses d3.scaleTime, d3.scaleLinear, and d3.scaleOrdinal with a category10 color scheme to encode city identity. Lines are generated with d3.line and a basis curve, while a custom color legend component renders SVG circles and text. Data comes from a CSV file loaded via d3.csv, with axes and gridlines produced by d3.axisBottom and d3.axisLeft.