The Many-Worlds Interpretation (MWI) is a theory in quantum mechanics that suggests every possible outcome of a quantum event actually occurs in its own separate universe. This means that when a particle is observed, it doesn't just take one path; instead, all potential paths happen simultaneously, creating a vast number of parallel universes. In this interpretation, every decision or event spawns new branches of reality. For example, if you flip a coin, one universe will see it land on heads, while another will see it land on tails. This concept challenges traditional views of reality and raises questions about the nature of existence and observation in quantum physics.