The Karl-Theodor-Bridge (Alte Brucke) in Heidelberg is a sandstone pedestrian bridge that goes across the Neckar River linking the old town on one side with the Neuenheim district on the other. It was built in 1786, and even though there were several other bridges before it in this location, it was the first one made of stone. On the city side of the bridge, there are two towers that once formed part of the city walls. They contain old dungeons which were used to hold criminals. Between the towers, you can see a plaque honoring the Austrian troops who helped defend the bridge against an attack from the French in 1799.
Another feature visitors will notice is a statue of a monkey holding a mirror. The monkey represents the idea that neither those who lived within the city walls nor those who lived outside the city were any better than the other, and that they should look over their shoulder as the cross the bridge to remember this. Other sculptures on the bridge include a monument to Prince Elector Carl Theodor, who had the bridge built, and one devoted to the Roman goddess Minerva.
The two towers of the Old Bridge stand at Obere Neckarstrasse. The road that runs on the bridge is Karlstrasse.