The Philosophenweg — Philosophers' Walk — runs along the sunny south-facing slope of the Heiligenberg on the north bank of the Neckar, offering the panoramic view of the Altstadt, the Alte Brücke, and the castle that appears on every postcard of the city. The path takes its name from the generations of academics and thinkers who walked it: Hegel taught at Heidelberg from 1816 to 1818, Goethe passed through multiple times, and Mark Twain described it in detail in A Tramp Abroad. The steep path connecting the bridge to the walk is called the Schlangenweg (Serpent Path).
The walk itself runs roughly east to west above the river for about two kilometres. The slope is warm enough to grow figs, almonds, and even some vines — a microclimate produced by the south-facing hillside and the warmth reflected off the river. Along the route are benches, a small garden created in memory of the Jewish philosopher Ernst Bloch, and a viewpoint near the ruins of a Bismarck tower at the western end. The walk is at its best in the late afternoon when the Altstadt rooftops and castle catch the low westerly light.
To reach the Philosophenweg from the old town, cross the Alte Brücke, turn left, and follow the riverside path a short distance before climbing the Schlangenweg. Allow an hour for a comfortable stroll in one direction, or combine it with a walk through the Neuenheim neighbourhood on the way back.