The coil winding for the central solenoid magnet was completed in Japan in 1999. The superconducting magnet provides a field of 2 T at the centre of ATLAS's tracking volume.
The prototype B-0 toroid coil arrived at CERN from the CEA laboratory in Saclay on 6 October 2000. At "only" 9 m in length this prototype is the largest toroid coil ever built.
The ATLAS cavern was handed over to CERN by the civil engineering contractors in a ceremony on 4 June 2003. This 12 storey access structure was one of the first items installed.
As the toroid magnet took shape, on 21 June 2005 the barrel calorimeter saw the first cosmic-ray events in situ.
The final barrel for the ATLAS Semiconductor Tracker (SCT), was delivered in September 2005. Its integration into the full barrel assembly followed a few days later.
Moving at 1 km/hour on a special trailer the first of the endcap toroids leaves the assembly hall in February 2007 before being cold-tested at 80 K, prior to installation in the cavern.
Many of the final systems of the ATLAS detector (seen here with the endcap calorimeter system withdrawn) were tested with cosmic-ray data in June 2007 in the third "milestone week" of global commissioning.
The final large piece of the ATLAS detector was lowered into the underground cavern on 29 February 2008. The "small" muon wheel safely made the 100 m journey in an hour and a half.