Even the album's promotional campaign is ambitious. U2 appeared on "Late Show With David Letterman" for five consecutive nights beginning March 2, a rarity for the band and a first for the show.

"Very early on we did a residency in our hometown of Dublin. We played at the Baggot Inn on Baggot Street on a regular Thursday night, when we were making our first album and first few singles," the Edge says. "We also did a string of shows in the month of July one year, might have been 1979. We called them the 'jingle balls' because we decked out the entire club in Christmas decorations in the middle of summer. That was at a club called McGonagles, which is no longer there. Since then we've not done anything like this, so it will be not a totally new experience, but something we haven't done in many, many years."

U2 has always approached its concerts as epics, according to longtime manager Paul McGuinness. "I don't think U2 have ever rested on their laurels as either a touring act or a recording act," he says. "We have an in-houseproverb: Every time we make a record we intend to break the band again, and that really is the discipline. If we released a record and didn't gain new fans, we'd be very disappointed. Naming no names, there are big touring acts whose new records are not successful or very interesting, and it has to be both for U2."

U2 will tour Europe through Aug. 22, then hit America starting Sept. 12 with a show at Soldier Field in Chicago; the band will play North America until Oct. 28 and work the globe until the fall of 2010.

In addition to its production firsts, U2360º will almost certainly become one of the highest-grossing tours ever. At $389 million, the band's 2005-07 Vertigo tour is second only to the Rolling Stones' A Bigger Bang.

After playing arenas in North America and stadiums elsewhere on its last few tours, U2 will play stadiums everywhere this time out.

"This is going to be completely different, and that's what makes it exciting--finding something new to bring to the touring culture," the Edge says. "It's hard to come up with something that's fundamentally different, but we have, I think, on this tour. Where we're taking our production will never have been seen before by anybody, and that's an amazing thing to be able to say."