At the University of Michigan in Ann Arbor, the Diag (/ˈdaɪ.æɡ/ DY-ag) is a large open space in the middle of the university's Central Campus. Originally known as the Diagonal Green, the Diag derives its name from the many sidewalks running near or through it in diagonal directions. It is one of the busiest sites on the university campus, hosting a variety of events including outdoor concerts, fundraisers, demonstrations, and sun bathing.
Many of the University's most frequented buildings are situated around the Diag, including West Hall, Randall Lab, the Shapiro Undergraduate Library, the Hatcher Graduate Library, and Angell, Mason, Haven, and Tisch Halls, among others.
The Diag is the separation of Church and State (bordered by State Street to the west and Church Street to the east).
A brass block "M", a symbol of the university, is embedded at the center of the Diag. Local legend has it that if a UM student steps on the M before taking his or her first blue book exam at the university, the student will go on to fail that exam. The only way to reverse this "curse" was to run naked from the campus belltower during the strokes of midnight to two statues of pumas at the Natural Science Museum, then back to the tower before it stopped ringing. This has been made considerably more difficult in recent years as the belltower no longer rings at midnight.
During the week before the annual football game against Michigan State University, members of the Theta Xi fraternity take turns guarding the inlaid "M" against vandalism by rival fans. A similar vigil takes place at Michigan State University known as "Sparty Watch" or "Sparty Guard" where members of the Spartan Marching Band guard the Sparty statue against vandalism.