Rae's Creek meanders through the 12th hole. The iconic Hogan and Nelson bridges cross the creek.
Why it's Crazy
Rae's Creek frames the front portion of the 12th green and runs behind the 11th green. On the 12th, it's not a terribly imposing hazard as players tend to just play long, so if they miss they'll end up in the bunkers or the azaleas, rather than the creek.
The crazy thing about Rae's creek is that, for as notable as it is, for as significant a part of Amen Corner lore as it is, the bridges which span it are nearly as famous and iconic as the hazard itself. The Hogan bridge, for example, was dedicated in 1958 and bears a plaque that reads:
This bridge dedicated April 2, 1958, to commemorate Ben Hogan's record score for four rounds of 274 in 1953. Made up of rounds of 70, 69, 66 and 69. This score will always stand as one of the very finest accomplishments in competitive golf and may even stand for all time as the record for The Masters tournament.