Syukoro Manabe, Klaus Hasselmann and Giorgio Parisi received the Nobel Prize in Physics from the Swedish Academy of Sciences in 2021 for their “groundbreaking contributions to the understanding of complex physical systems”. In the first half of the presentation, we briefly present the key results of the winners. We then discuss Parisi's findings on disordered systems in more detail. In this context we describe the different forms of fluctuations due to disorder and their role in the collective behavior of many-body systems. We pay special attention to the replica symmetry breaking conditions in spin glasses, which represent a new form of organization of matter.