O - Bellagio's water-based Cirque du Soleil production

O is a permanent Cirque du Soleil theatrical production at the Bellagio that opened with the resort in 1998. The show is staged in a custom theater that incorporates a large aquatic stage (a pool holding roughly 1.5 million gallons of water) and specialized stage machinery to support synchronized diving, acrobatics, and aerial acts. O is one of the few long-running, purpose-built aquatic theater productions in the world and has been performed continuously at the Bellagio for decades.