U2 is about to begin their highly anticipated world tour, the U2 360 tour, and to say they've raised the bar for themselves would be a bit of an understatement. In less than two weeks, the Irish rockers will be embarking on their first global trek since its massively successful "Vertigo" tour, bringing along a massive, $170 million stage structure that's come to affectionately be known as The Claw.

In taking the huge financial risk of their radical stage set-up, U2 hopes to set a new idea for stage configuration that will change large-scale concerts in the future.

Speaking about the touring project he's been working on for the past seven years, frontman Bono says "The Claw is all to do with how you can play outdoors without using a proscenium stage with a big bank of speakers on the left and right. Every outdoor stage show you've ever seen uses that configuration. This idea we're now working on will mean more people can fit into the shows, there will be better sight lines and everyone will be closer to the action," he says.

Check out a preview of the tour - and The Claw, here:

The giant four-legged Claw will be set in the middle of the venue, and in the center there will be a revolving stage. All the technical hardware is hidden inside the four legs of the structure, and at the top is a huge video screen which will offer simultaneous footage of the concert to the farther audiences at the show. 

Over 130 feet high, weighing 390 tons and requiring 180 trucks to transport it from venue to venue, U2 have three different Claws at their disposal. While they are playing on one of them, the second one is being set up at another venue and the third one is being transported somewhere else.

Long-time U2 associates Willie Williams and Mark Fisher will be working as show directors for the 18-month tour. "Everyone who sees it says that it looks like something different," says Williams. "It does look as though it has escaped from a giant space aquarium."

The Claw was inspired by the four-legged Theme Building at Los Angeles airport. "Our work is all to do with the logistics of building a very large piece of technical infrastructure in a very short time, and to make something interesting out of it," says Fisher. "Why do people go to shows like this in the digital age? It's for the huge collective experience, the social and spatial, and memories. This set will contribute by creating a massive sense of anticipation and delivering an amazing kinetic performance."

The base goal of The Claw is to create a feeling of intimacy for crowds of up to 90,000 people - no easy feat by any standard.

U2 have always tried to push the envelope in their live context. The Zoo TV tour of 1991 was a massively ambitious, high-tech affair with banks of giant video screens displaying imagery that corresponded with the music. The follow up-tour, 1997's PopMart, was a celebration of kitsch, an over-the-top take on pop consumerism, with huge McDonald's-style "Golden Arches" on stage and a giant lemon from which the band members would emerge. It was a gaudy, shimmering affair.

When it comes to the "Claw" stage design, Production Director Jake Berry said, "Seeing it here is something else. I think jaws are going to drop when people come through those doors on opening night."

"I think it will take people's breath away when they arrive, a real statement that U2 are in town," Fisher said, "But when the band come on stage it will disappear, it will all be about the communication between the band and the audience."