The rock band U2 is at the top of its game, and back on tour. Anthony Mason will look behind-the-scenes:

It's been four years since U2 last toured together. Four years since Bono, The Edge, Adam Clayton and Larry Mullen Jr., conquered the world, selling more than seven million tickets and earning more than $700 million -- leading Rolling Stone magazine to label them "the biggest band on Earth."

"Your last tour was your most successful tour in history," said Mason.

"Right, thank God!" laughed Bono. "That was great. Loved hearing you say that, Anthony! We're going to get on just great!"



"That does mean something to you, though?"

"Yeah, of course it does. I mean, we're a live band."

"Are you competitive about that sort of thing? I mean, did you feel yourself competing against the Stones while you were touring?"

"I remember Mick Jagger came to see us at Pop Mart," Bono said, referring to U2's 1997 tour. "And we'd really gone to some lengths in Pop Mart, and he said, 'Oh, this is getting like "Star Wars."'"

Their new show, the "Innocence + Experience Tour," is still big. They've left the huge outdoor stadiums and moved indoors, playing smaller arenas. "They're club gigs," Bono laughed.

But they're still travelling with 24 semi trucks full of gear. "The lion tamers are over there," Bono said, showing Mason around the floor of the Rogers Arena in Vancouver. "Bring out the camels! It's the circus come to town."

Mason caught up with the band on the road, first in Vancouver, where U2 spent a month rehearsing.



"This is the behind-the-scenes stuff that no one gets to see," said The Edge, who took Mason through the band's subterranean set up, under the stage, including "Guitar World" -- a collection of instruments, from a new Fender to a Chet Atkins Country Gentleman from the mid-'60s. "Every guitar in the show has to have a spare," he said.

A U2 tour is a blend of both high and low tech. The Edge uses antique amps: "It's still valve technology. It's exactly the same as it was in the '50s. And that is, for whatever reason when you plug in an electric guitar to one of these, it's just the way it should sound."

Correspondent Anthony Mason with U2's Bono. CBS News

But then there's the mammoth LED screen suspended above the arena floor: "We basically have this double-sided screen," The Edge said. "But we can also climb into the image."

The Edge fits into a projection of Anthony Mason's hand. CBS News

During their concerts the band will climb into what feels like a giant cage: "This'll be our home for the next year or so!" The Edge said.

It's different, he admitted, but it's transforming the concert experience.

But on opening night in Vancouver the tour almost ended, when The Edge went over the edge, falling off the stage.