Macroscopic quantum phenomena are things that happen when there are lots and lots of tiny particles (called 'quantum particles') all behaving at the same time. The particles are so small that they obey special laws of nature called quantum laws. These quantum particles can interact with each other in surprising ways, creating patterns and effects that can't be explained by regular, everyday laws. For example, when enough quantum particles all get together in one place, they can start to act like they are a single, bigger particle - even if they are really still lots of little particles.