Curiosity is as old as humankind, and it is CERN's raison d’être. When the Laboratory was founded, the structure of matter was a mystery. Today, we know that all visible matter in the Universe is composed of a remarkably small number of particles, whose behaviour is governed by four distinct forces. CERN has played a vital role in reaching this understanding.

Throughout the 1960s, theories were advanced to explain two forces – the weak force and the electromagnetic force – in the same framework. In the 1970s, a CERN experiment brought the first experimental evidence for these ideas, and in the 1980s the discovery of the W and Z particles – carriers of the weak force – brought confirmation of the theory. CERN researchers Simon van der Meer and Carlo Rubbia shared the Nobel Prize in physics for this discovery the following year.

Throughout the 1990s, CERN experiments designed in the light of this discovery tested the so-called electroweak theory with extreme precision, putting it on solid experimental ground. In 2010, the LHC started to provide particle collisions in a new high-energy domain, leading to the discovery at CERN of a Higgs boson – long sought as the particle linked to the mechanism that gives mass to elementary particles.

Have we reached the end of the road in understanding nature? Far from it. There is still much to learn about the Higgs boson, and many other puzzles remain about how and why matter in the Universe is the way it is.