ALICE (A Large Ion Collider Experiment) is one of eight detector experiments at the Large Hadron Collider at CERN. The other seven are: ATLAS, CMS, TOTEM, LHCb, LHCf, MoEDAL and FASER. Introduction ALICE is optimized to study heavy-ion (Pb-Pb nuclei) collisions at a centre of mass energy up to 5.02 TeV per nucleon pair. The resulting temperature and energy density allow exploration of quark–gluon plasma, a fifth state of matter wherein quarks and gluons are freed. Similar conditions are believed to have existed a fraction of the second after the Big Bang before quarks and gluons bound together to form hadrons and heavier particles. ALICE is focusing on the physics of strongly interacting matter at extreme energy densities. The properties of the quark–gluon plasma and the understanding of quark deconfinement are key issues in quantum chromodynamics (QCD). The results obtained by ALICE corroborate the understanding of color confinement and chiral symmetry restoration. Recreating the primordial form of matter, quark-gluon plasma, and understanding how it evolves is expected to shed light on questions about how matter is organized, the mechanism that confines quarks and gluons and the nature of strong interactions and how they result in generating the bulk of the mass of ordinary matter. Quantum chromodynamics (QCD) predicts that at sufficiently high energy densities there will be a phase transition from conventional hadronic matter, where quarks are locked inside nuclear particles, to a plasma of deconfined quarks and gluons. The reverse of this transition is believed to have taken place when the universe was just 10−6 s old, and may still play a role today in the hearts of collapsing neutron stars or other astrophysical objects. History The idea of building a dedicated heavy-ion detector for the LHC was first aired at the historic Evian meeting "Towards the LHC experimental Programme" in March 1992. From the ideas presented there, the ALICE collaboration was formed and in 1993, a Letter of Interest was submitted. ALICE was first proposed as a central detector in 1993 and later complemented by an additional forward muon spectrometer designed in 1995. In 1997, ALICE received the green light from the LHC Committee to proceed towards final design and construction. The first ten years were spent on design and an extensive R&D effort. Like for all other LHC experiments, it became clear from the outset that also the challenges of heavy ion physics at LHC could not