  The wireless metaverse will create diverse user experiences at the
intersection of the physical, digital, and virtual worlds. These experiences
will enable novel interactions between the constituents (e.g., extended reality
(XR) users and avatars) of the three worlds. However, remarkably, to date,
there is no holistic vision that identifies the full set of metaverse worlds,
constituents, and experiences, and the implications of their associated
interactions on next-generation communication and computing systems. In this
paper, we present a holistic vision of a limitless, wireless metaverse that
distills the metaverse into an intersection of seven worlds and experiences
that include the: i) physical, digital, and virtual worlds, along with the ii)
cyber, extended, live, and parallel experiences. We then articulate how these
experiences bring forth interactions between diverse metaverse constituents,
namely, a) humans and avatars and b) connected intelligence systems and their
digital twins (DTs). Then, we explore the wireless, computing, and artificial
intelligence (AI) challenges that must be addressed to establish
metaverse-ready networks that support these experiences and interactions. We
particularly highlight the need for end-to-end synchronization of DTs, and the
role of human-level AI and reasoning abilities for cognitive avatars. Moreover,
we articulate a sequel of open questions that should ignite the quest for the
future metaverse. We conclude with a set of recommendations to deploy the
limitless metaverse over future wireless systems.
