A masterpiece of civil engineering The excavation of the Large Electron–Positron tunnel was Europe’s largest civil-engineering project prior to the Channel Tunnel. Three tunnel-boring machines started excavating the tunnel in February 1985 and the ring was completed three years later. The first beam circulated in the LEP on 14 July 1989 and, during its 11 years of research, the LEP experiments provided a detailed study of the electroweak interaction. To this day, the #LEP remains the largest ele