Cirque du Soleil’s “O” has achieved some truly magical milestones recently, celebrating its 20th anniversary in December of 2018 and then passing the 10,000-show mark on Sept. 1. Anja Wyttenbach has been a part of this iconic Las Vegas production since day one. Born in Basel, Switzerland, the acrobatic and versatile performer, a veteran of touring circus productions, was developing some innovative aerial acts in Montreal when the creators of “O” came calling. “It was right place, right time,” she says of being awarded the role of Aurora in the game-changing show that premiered on Oct. 17, 1998, at the newly opened Bellagio. “Everyone was taking a chance on something new and you don’t know what to expect.”

Today, “O” is such a big part of Cirque and Las Vegas. What was it like in the beginning?

It was pretty crazy and very intimidating at first. I remember seeing the theater being built before Bellagio was open, when I came to town and was apartment hunting. The pool wasn’t filled and they had my trapeze hanging over it. They were laying it all out. But doing the actual opening shows, it felt like being a movie star. There were 500 reporters from all over the world in the first few rows and everyone was dressed up. That was more than 20 years ago, so it was a little different then. It makes me think of how lucky we’ve been and had such super audiences. For something like 10 years, we were 99 percent sold out.

You balance on your head above the pool. Has your role changed much over the years?

It’s evolved a little. “O” does have a little bit of a story, but it’s subtle, and (writer and director) Franco Dragone wanted it that way. You have Philemon coming out of the audience and getting thrown into the elements, and I’m Aurora, sort of his fantasy, and he sees me here and there. He has other friends but as he grows in the show, he has more independence; he’s not this lost child anymore. It’s still such a beautiful show.

When you’re on the trapeze, it’s really a climactic moment in this magical experience.

What’s nice is that it’s a quiet act but very impressive. I think it stands out because everybody is usually very quiet at that moment—in a show that’s very hectic. I used to do a bicycle act and then I started doing head-balancing on my partner’s head on this unicycle. That’s not very easy either, but that’s how I got into it

It sounds impossible, and your act in “O” looks impossible. How different does it feel to balance upside down?

It is different but it’s like any acrobatics or even doing yoga in that once your body gets used to it, you just do it. The trapeze is very different from the floor. The floor is unforgiving. I prefer the trapeze. When I first started this act, it was super hard because the cables (for the trapeze) are extremely heavy and every move I’d make would give way to that cable, and it throws you off. Now I don’t feel it anymore, but when I train my backups, they can feel it.

You’ll be training more performers now that “O” is about to move to seven nights a week.

I think that will be better for me. My backup now gets only two shows a week so she’ll get to work more. I’m looking forward to that. I really do enjoy it still. I think the big swing goes about 30 miles per hour and I start out at 45 feet up. It’s a cool feeling. It keeps you on your toes, even after thousands of shows.