My informant is in high school where there is a legend that there is a series of tunnels that go under the campus that one could use to go to another side of the campus without being seen. He has heard this rumor from other students and whenever a teacher is seen somewhere unexpected it is accredited as evidence of a tunnel. This legend is often tied in with another legend stating that one of the classrooms used to be a bomb shelter until the school needed extra space and that the closet in this classroom has a trapdoor to the tunnels in it.
This legend is similar to ones that other high school have, but each has their own variation on it like this school has the association with the bomb shelter being the starting point. This is a legend that no one believes, but is still told over and over again by the different classes going through the school. It is a form of bonding between the students as they tell stories about what makes their school unique.