Human conception of the size and diversity of the universe has changed dramatically throughout history. The existence of other planets, stars, and galaxies was once wild speculation. However, we now have observational evidence that the universe contains hundreds of billions of galaxies, each with hundreds of billions of stars. Is this all that there is? A nexus of ideas from theoretical cosmology, quantum gravity, and string theory suggests that it isn't. Rather, these theories predict the existence of an enormous diversity of regions, each of which could rightfully be called a universe; these theories suggest that we inhabit a Multiverse. Perhaps most excitingly, this idea can be tested with observations of the large-scale structure of the observable universe. This talk will explore the idea of a Multiverse and the most recent constraints on its properties from cosmology.