This example shows a time-series line chart of stock closing prices, with a tooltip that highlights the nearest data point as the mouse moves across the chart. The chart uses D3.js version 3.5 to parse dates, scale the axes, and draw the line and axes as SVG elements. A hidden circle is repositioned using the `bisectDate` function and the `d3.mouse` coordinates, appearing only during mouseover. The data comes from a CSV file with date and close price columns, rendered with a steel-blue line and grey axes.