In the heart of Europe, one of the largest and most complex machines ever built by humans has come into operation: the Large Hadron Collider (LHC). It opens a window into a new world filled with many mysteries: What gives particles of matter their mass? Are there hidden dimensions of space? Is there a deeper connection between particles with different spins (supersymmetry)? What is dark matter, which permeates our universe? Does the Higgs particle exist? With this book, the reader dives into this wonderful world that we humans have discovered in modern times: atoms and their substructure of quarks and leptons, the enigmatic quantum mechanics, particles of light, Einstein's fabric of space and time, the four fundamental forces, and finally the new world that the LHC is currently exploring, where we discover Higgs particles and supersymmetry.