The chiral anomaly is a phenomenon in quantum field theory where the conservation of chirality, a property related to the handedness of particles, is violated in certain conditions. This occurs in systems with gauge fields, such as those described by the Standard Model of particle physics, leading to unexpected results in particle interactions. In simple terms, while chirality is typically conserved in classical physics, the presence of strong electromagnetic fields can cause a mismatch between the number of left-handed and right-handed particles. This anomaly has important implications in various areas of physics, including the behavior of fermions and the study of topological insulators.