Master classes are a unique opportunity for high-school students, where they can hunt particles at the Large Hadron Collider [LHC] and analyse real data from the experiments. Each year, in spring, research institutes and universities around the world open their doors and invite students for daylong visits. This year’s International Master classes were organized in March, under the auspices of the International Particle Physics Outreach Groups [IPPOG], and attracted more than 10 000 students.In the Master class, students gained insight into the international organization of modern research in…