The Large Electron-Positron Collider (LEP) was a particle accelerator located at CERN, near Geneva, Switzerland. It operated from 1989 to 2000 and was designed to collide electrons and positrons at high energies. This allowed scientists to study fundamental particles and their interactions, contributing to our understanding of the Standard Model of particle physics. LEP was instrumental in discovering the Z boson and measuring its properties, which helped refine theoretical predictions. The collider had a circumference of about 27 kilometers and was the largest of its kind at the time. After its decommissioning, it was replaced by the Large Hadron Collider (LHC).