This interactive line chart visualizes daily high temperatures for New York, San Francisco, and Austin from October 2011 to April 2012. Built with d3.v7, it renders SVG line graphs with a smooth basis curve. Users can hover over city labels to highlight a specific line, dimming others, and click to toggle a city's visibility. The chart also supports zooming on the time axis via the `d3.zoom` API, which rescales the x-scale and redraws the lines with the `d3.line` generator and `d3.curveBasis`.