Heidelberg's 200m-long ‘old bridge’, built in 1786, connects the Altstadt with the river’s right bank and the Schlangenweg (Snake Path), whose switchbacks lead to the Philosophenweg (Philosophers' Walk).
Next to the tower gate on the Altstadt side of the bridge, look for the brass sculpture of a monkey holding a mirror. It's the 1979 replacement of the 17th-century original sculpture.