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.