Quantum nonlocality refers to a phenomenon in quantum mechanics where particles can instantaneously affect each other's states, regardless of the distance separating them. This means that when two particles are entangled, a change in the state of one particle will immediately influence the state of the other, even if they are light-years apart. This behavior challenges our classical understanding of space and time. This concept is often illustrated through the Einstein-Podolsky-Rosen (EPR) paradox, which questions whether quantum mechanics provides a complete description of physical reality. Experiments, such as those involving Bell's theorem, have confirmed the existence of quantum nonlocality, suggesting that information can be shared between entangled particles faster than the speed of light, defying classical intuitions.