Winding past monuments, towers, ruins, a beer garden, and an enormous Thingstätte (amphitheatre) built by the Nazis in 1935, the 2.5km-long Philosophers’ Walk has captivating views of Heidelberg's Schloss, especially at sunset when the city is bathed in a reddish glow. Access is easiest via the steep Schlangenweg from Alte Brücke. Don't attempt to drive up as the road is narrow and there's nowhere to turn around at the top.