''O'' Show, Las Vegas ''O'', Cirque du Soleil, the Las Vegas performance at the Bellagio Hotel, including aerialists, synchronized swimming, contortionists, clowns, high diving and fire dancing, has one common bond: water, 1.5 mega gallons of it. Only a few, a very few, mostly ushers and concessionaires, are not required to be certified scuba divers. It's not a prerequisite for the audience to be certified divers or water lovers. In fact, it's not until near the end of the show that the audience is made aware of the essential safety divers as they ''flipper up'', like seals on the pool's apron, to take their applause. My first experience with ''O'' was a present for my 50th birthday a year ago which included a back stage tour by Head of Aquatics, Alan Goldberg. I thought somewhere there was a Goldberg relation, after all, Alan was a former lion tamer and myself, an offshore commercial diver. So armoured with the show's artistry and technical intrigue, I returned a year later to watch ''O'' again from the audience and then from the light booth as a Sport Diver writing assignment. The following are some of the unique elements that divers and water people will find of interest. The ''O'' Dive Site:''O'' is a custom built dive site that seats 1,800 people. The height from the bottom of the 25 foot pool to the top of the high steel in the grid is 145 feet, the equivalent of a nine and a half story building. There are 134 technicians, 81 performer/artists and 16 technicians (e.g. SCUBA divers) in the water during each show. The only perceptible hint, that hidden behind the theatre curtain there is a pool, is a faint waft of chlorine that quickly fades. As the audience is seated, there is a free falling drip, from high above, caught precisely in one of the clowns bucket. For the next ninety minutes, the dive site is transformed into a mystical world of rolling fog, roiling water, lighting that creates dawn and dusk, fire that howls and then goes to silence so that only the lapping of the water is heard. It is hydraulica. At first glance it seems so easy to design this weather. It isn't. In talking to Alan Goldberg, it took 20 designers and three years of intense study and testing to result in this one-of-a-kind aquatic environ. In fact, a 20 by 30 foot test pool was built to determine the affects of various materials in a theatrical setting. In order to keep the atmosphere sufficiently warm for the performers and sufficiently cool for the audience, ''O'' engineers created a micro-climate by using ventilation techniques to stratify the air in the theatre. One method provides an imperceptible 55 degree F cold air vent under theatre seats which keeps the audience at 72 degrees F and the stage much warmer. The wire mesh theatre dome acts as a chimney allowing the warmer air to escape. This also allows control of some of the special affects, like fog banks, to be precisely placed. The appearance is much like a ship gliding into a mist. 6000 feet of perforated hose is configured in the pool bottom to produce an air train that both hides under water activity and creates transitions for actors to emerge and, of course submerge. The control of the bubbles creates naturist affects so at times; the pool has an eerie sense of mystical tide pool. To minimize sound disturbance caused by waves, the pool is surrounded by a series of gutters containing various size pebbles. The ''O'' pool is masked by a vegetation curtain made of a special vapor resistant-plastic. The set invokes a scene, perhaps of a dive site in a hidden jungle pool. ''O'' Props and Equipment:The pool contains seven sophisticated hydraulic lifts to make a conventional stage surface that may be puddle-like, dry, or retracted to create other shapes. From these lifts, emerge giant anemones, over-sized carousel horses gliding through the water, motorized umbrellas, a floating crocodile mask, a half submerged house and a stainless steel grand piano. Similar to the pool, there was unique experimentation and testing of the props. Alan Goldberg says ''things that appear to move effortlessly through the water are actually extremely complex. For example, each horse weighs approximately 750 pounds. Inside the horse is a floatation module which balances the horse to the waterline and propulsion units hidden under the tails. The artist steers it with a lever.'' I asked Alan if it was possible to turn this carousel horse into a sea horse. Alan said with ''O'', ''anything is possible.'' The crocodile mask, which can carry nine performers, is operated by a technician underwater. The moveable Barge is 1.5 tons of fiberglass and foam. It maneuvers into place with the aid of seven divers, holds 20 performers, and has 14 breathing stations on it's undercarriage for artists who must remain submerged during extended periods of the performance. Sport divers use light and back-up lights for a number of reason, of course to navigate in darkness and to bring color illumination at depth. In ''O'', a thesis could be written on its lighting adventure. A total of 1815 lights and 230 color scrollers provide 4 million watts, capable of turning night into a water aurora borealis. In addition to the topside sound system, the pool has twenty-three underwater speakers with an additional speaker known as a Rover, used when the aquatic masking is active so the performers and divers can still hear cues and music. The Acts and Actors:''O'' acts in, on and above the water with a troupe representing 18 nationalities. The synchronized swimmers are world class Olympians coached by former Canadian gold medalist Sylvie Frechette. A group of 4 high divers, made up of cliff and exhibition divers launch themselves from 60 feet above into a 10 foot opening in the pool floor. The contortionists, from Mongolia, arrive via the sky and perform their act on a platform surrounded by water. Their lithe bodies resemble somewhat the weightlessness of SCUBA divers except they are land bound. For SCUBA divers, it is a beautiful mental juxtaposition of how we twist our weightless bodies to peer into tight spots while the earth bound contortionists, with precision, control every muscle on their bodies with seeming ease. These are just a few of the acts. It should be noted that Cirque Du Soleil uses no animals in any of its productions. Many of the performers are actually ex-circus who have used Cirque as a means to settle down. The Aquatics Team:This is Alan Goldberg''s team and it has many functions including rigging, moving sets, assisting performers, and foremost, SAFETY. Job descriptions include riggers, carpenters, and artistic handlers, among others; remember this is the theatre. However, it is fair to say the theatre names translate into a highly skilled group of working SCUBA and surface supplied air divers. ''O'' is illusory in the use of the divers. Although almost always hidden from the audience¿s view by lighting, aeration, and camouflage; they are in force. There may be as many as 20 performers beneath the water at once waiting to enter from above, emerge from below or exit into the wings, always watched over by 16 SCUBA divers, two who are outfitted in surface supplied AGA full-face masks with communication systems. The complexities of this underwater scene, given the moving lifts, often working in the dark, and the fact that of so many performers are coming and going, lends itself to imagining a cloaked underwater busy city street corner. Not only can there be no collisions but the timing of the 800+ cues (often given by audio tones or light) must be kept in perfect sync. If a certain scene becomes out of sync, it is the SCUBA divers who give signs to regulate the tempo back to its focal point. The SCUBA divers do two shows per night with a max combined profile of 3 hours at 25 feet. While this is well within no-decompression limits, all divers wear dive computers to keep track of bottom time as well as ascent rates. The real key in this environment is keeping your station and ascent rates. This is a place were buoyancy skills rule. Alan says there is nothing worse than seeing a fin tip exposed during a scene where all eyes are on the performers. Remember the SCUBA divers don't exist to the audience. Coordinating the aquatics team is like supervising a complex diving project. To make it all happen, hidden high away, 56 feet up, in a spot aptly named the crow's nest, Alan is able to monitor the entire theatre from a specialized console. He keeps a close eye on the underwater activities via three underwater video cameras (there are also 26 other video camera mounted to provide different above water views with 39 video monitors located back stage). He wears a head set with 2 channels, one for the 2 divers with AGA comm sets and one for the backstage channel. It's a lot of multi-tasking! In the panel there is a covered red distress button (E-stop) that can be switched to shut down all electrical and mechanical systems. In 1257 shows, there has not been a single accident. Camaraderie:One unifying element of the cast is that they are all SCUBA certified (PADI). Alan, a PADI instructor, certifies each diver to open water diver. The open waters take place in Lake Mead so all the performers have a baseline for some cold and dark conditions. In addition to this, specialized training is given which focuses on theatre. The San Jose Mercury news says that O is ''a wildly exciting show that combines guts of daredevils with the soul of artists.'' The ''O'' SCUBA divers provide the needed safety net to make it all happen. While leaving the exhilaration, Brigitte Belanger, Publicist for ''O'', and Steve Warner, Assistant Technical Director, asked if I had any final questions. I did, but the intrigue and mystere ''O'' were far better than an answer. There is no island or sea or shore quite like that of ''O.''