Actually if it's througout the career (as a total) I ould think of U2 as the last 4 tours were seen by over 4 million people alone not to mention previous tours and special events (superbowl, etc). Shows sometimes were up to 100000 people. That may not be the single biggest event but overall, I am pretty sure U2 would be up there!
what rock band has performed before the most paid attendees during its career?