A streaming area and line chart visualizes environmental sensor readings, depicting how Humidity changes over Time. The example demonstrates loading a CSV file with `d3.csv`, parsing the `Time` column into JavaScript `Date` objects, and numerically coercing the `Humidity` values. Using D3 v5, it renders an SVG area chart with a red gradient fill and a smooth line, animating the visualization by periodically splicing new data points into the dataset and redrawing the paths within a transition loop.