Where did all the antimatter in the universe go? At the birth of our universe, during the Big Bang, equal amounts of matter and antimatter were created. But today, 14 billion years later, when we look around at the universe, we see it is composed almost entirely of matter. At CERN, the European Laboratory for Particle Physics, we are carrying out experiments to measure tiny differences between the fundamental particles and their antiparticles, as well as producing and studying atoms made from antimatter: anti-protons and anti-electrons (also known as positrons). A hundred years ago, scientists didn’t know antimatter even existed, but today it is used for medical diagnosis and industrial applications. Antimatter matters is an opportunity to learn what we now know about antimatter, how we know it, and how it is used in everyday life.