L3
The L3 experiment was one of the four large detectors on the Large Electron–Positron Collider (LEP). The detector was designed to look for the physics of the Standard Model and beyond. It started up in 1989 and stopped taking data in November 2000 to make room for construction of the Large Hadron Collider (LHC). Now, the ALICE detector sits in the cavern that L3 used to occupy, reusing L3's characteristic red octagonal magnet.[1]
For more information, see Wikipedia.