The visualization displays yearly average rainfall and temperature in Germany from 1991 to 2015 as a dual-line chart, with red lines for temperature and blue lines for precipitation. It uses D3.js v5.7.0 with SVG rendering, leveraging `d3.nest()` to group raw CSV data by year and `d3.mean()` to compute annual averages. The chart implements linear scales, axis generators (`d3.axisBottom`, `d3.axisLeft`, `d3.axisRight`), and line generators to plot the two time series, with labeled axes for clarity.