Geneva, 29 February 2008. Today the ATLAS collaboration at CERN celebrates the lowering of its last large detector element. The ATLAS detector is the world’s largest general-purpose particle detector, measuring 46 metres long, 25 metres high and 25 metres wide; it weighs 7000 tonnes and consists of 100 million sensors that measure particles produced in proton-proton collisions in CERN’s Large Hadron Collider (LHC). The first piece of ATLAS was installed in 2003 and since then many detector elements have journeyed down the 100 metre shaft into the ATLAS underground cavern. This last piece completes this gigantic puzzle.