The concept of the multiverse suggests that our universe is just one of many, possibly infinite, universes that exist simultaneously. Each universe may have different physical laws, constants, and even dimensions, leading to a variety of possible realities. This idea arises from theories in cosmology and quantum mechanics, where different outcomes can occur in parallel universes. Multiverse theories can be categorized into several types, including the many-worlds interpretation of quantum mechanics, which posits that every decision creates a branching universe. Other models, like the inflationary multiverse, suggest that different regions of space can undergo varying rates of expansion, leading to distinct universes.