"O" is Cirque du Soleil's long-running water show at the Bellagio, built around a stage that turns into a vast pool. Divers, acrobats, swimmers, and aerial performers move in and out of the water with the kind of precision Las Vegas does best.
It is a polished Strip spectacle rather than an intimate theatre night, but the staging is genuinely impressive. Book ahead for good seats, especially on weekends.