Last fall, the Cirque du Soleil's "O" marked its 10,000 performance. Of all the Las Vegas Cirque shows, this is perhaps the most beloved, or at least the most mesmerizing. "O" opened in 1998 and has been a smash hit ever since.

As opposed to other Cirque du Soleil shows—and most other modern circus shows—"O" is a water-based show that, since its inception, has spawned and outlasted many imitators.

The show's acts are some of Cirque's most incredible and include high divers descending from near the ceiling of the 1,800-seat theater into a 1.5 million-gallon pool that acts as the stage. There's also a boat that doesn't reside in the water but rather over the pool, serving as a vessel for acrobats to perform gymnastic feats that wow the crowd.

Many of the acts start and take place fully in the gigantic pool, including synchronized swimmers that combine elegance, timing and creativity as they use the giant aqua stage to their advantage. The technical merits match the imagination and execution of the acts, making this a show unlike any other in Las Vegas—and anywhere else around the globe.

Bellagio, 7 & 9:30 p.m. daily, 7 p.m. show only Jan. 12-15, starting at $99 plus tax and fee. 702.693.8866