The lost continent of Mu is a mythical landmass that some theorists and authors claim once existed in the Pacific Ocean. It is often described as a vast, advanced civilization that sank beneath the waves thousands of years ago, leaving only traces in legends and ancient texts. Its supposed location is usually placed between Asia and the Americas.

While Mu, Atlantis, and Lemuria are all mythical lost lands, they differ in their origins and details. Atlantis, described by Plato, was said to be an advanced civilization that existed near the Pillars of Hercules (modern Strait of Gibraltar) and sank due to divine retribution. Lemuria was theorized as a landmass in the Indian Ocean to explain the distribution of certain species, a concept later dismissed by plate tectonics. Mu, on the other hand, is primarily associated with the Pacific Ocean and is often linked to spiritual or pseudo-historical theories rather than scientific discussions.

Proponents of Mu's existence often cite ancient writings, such as James Churchward's claims based on deciphered Naacal tablets, as evidence. Additionally, some point to similarities in ancient architecture, symbols, and myths from Pacific and Central American cultures. However, mainstream archaeology and geology have found no concrete scientific evidence to support the existence of Mu.