The Free Expression Tunnel opened in 1939 to connect North and Central campus, which are separated by railroad tracks. Since the 1960s, the university has been promoting it as a place for students to... The Free Expression Tunnel opened in 1939 to connect North and Central campus, which are separated by railroad tracks. Since the 1960s, the university has been promoting it as a place for students to graffiti without interference in order to cut down on illegal graffiti on campus. The tunnel underwent renovation in 2006 to make it more accessible to the handicapped. Heavy rainfall can cause the tunnel to flood; after a storm in July 2003, water levels reached five feet.