The first bar I visited in Freiburg was Schlappen – in mid September 1992. The sign is visible just behind the street light on the left. The word is generally understood to mean "slipper," but it could also mean someone who is exhausted – there is no slipper or other footwear on the sign.
As you see from the picture, this street divides up as a Y-junction. When I arrived in Freiburg, I do not believe there was a specific name for this place, but it became known later as the Bermuda Triangle. A quick Google search indicates that Bermuda Triangle was not widely used as a place name before 2005.
The Salatstube that you see in the center of the picture later moved to Schwarzwald-City (the closest thing downtown Freiburg has to a mall) and was replaced by a Burger King. Across the street from Schlappen was also a disco, and there was another one down the street.
By the late 2000s, this area had become a hangout for students. Increasingly, drunk people became violent. Eventually, alcohol drinking was banned from the Triangle, and a shoe store has replaced Burger King. I believe the Triangle has calmed down.
Schlappen remains, but it was renovated about a decade ago (not sure when). When it reopened, it began stressing the fact that the building was constructed over an 11th century latrine, which you can now see (you couldn't before) when you go to the john. When the weather is good, tables stand where the bikes were in the picture above.