be really met (nor paid for) with existing technology. Significant advances, and in some cases a technological break-through, would be required to build on the ground what physicists had dreamed up on paper for their experiments. The initially very broad and later more focused, well organised and well supported R&D effort, which was sustained over most of the 1990s, has led to many evolutionary and some revolutionary advances in detectors, electronics and computing. Designing a dedicated heavy-ion experiment in the early '90s for use at the LHC some 15 years later posed some daunting challenges. The detector had to be general purpose - able to measure most signals of potential interest, even if their relevance may only become apparent later - and flexible, allowing additions and modifications along the way as new avenues of investigation would open up. In both respects ALICE did quite well, as it included a number of observables in its initial menu whose importance only became clear later. Various major detection system were added, from the muon spectrometer in 1995, the transition radiation detectors in 1999 to a large jet calorimeter added in 2007. ALICE recorded data from the first lead-lead collisions at the LHC in 2010. Data sets taken during heavy-ion periods in 2010 and 2011 as well as proton-lead data from 2013 have provided an excellent basis for an in-depth look at the physics of quark–gluon plasma. After more than three years of successful operation, the ALICE detector is about to undergo a major programme of consolidation and upgrade during the long shutdown [LS1] of CERN's accelerator complex. A new subdetector called the dijet calorimeter (DCAL) will be installed, and all 18 of the existing ALICE subdetectors will be upgraded. There will also be major renovation work on the ALICE infrastructure, including the electrical and cooling systems. The wealth of published scientific results and the very intense upgrade programme of ALICE have attracted numerous institutes and scientists from all over the world. Today the ALICE Collaboration has more than 1800 members coming from 176 institutes in 41 countries Heavy-ion collisions at the LHC Searches for Quark Gluon plasma and a deeper understanding of the QCD started at CERN and Brookhaven with lighter ions in the 1980s. Today's programme at these laboratories has moved on to ultrarelativistic collisions of heavy ions, and is just reaching the energy threshold at which the phase transition is expected