Cosmic rays are charged particles, such as protons, electrons, and atomic nuclei, that are accelerated to high energies by various astrophysical processes, such as supernovae explosions and black hole jets. They can travel across vast distances in space, interacting with various magnetic fields and matter along the way. When cosmic rays reach the Earth’s atmosphere, they collide with atoms and molecules, creating a cascade of secondary particles in what is known as an air shower. Studying cosmic rays can help us understand the most energetic processes in the universe, as well as the influence of cosmic rays on the formation of galaxies and the evolution of life on Earth.