Quantum entanglement is one of the most fascinating and mysterious phenomena in modern physics. It lies at the heart of quantum mechanics, the scientific theory that describes how particles behave at the smallest scales of nature. Entanglement challenges our everyday understanding of reality, distance, and causality. When two or more particles become entangled, their properties become deeply connected, even if they are separated by vast distances. A change in the state of one particle immediately influences the other, regardless of how far apart they are.