The £789-million boondoggle on the Thames in East London, is a dome the volume of ten St Paul’s. It’s where the gargantuan acts from Dolly to Gaga to Kylie to Monty Python appear, packing in their own religious followings, in a 20,000-place arena (ladies, there are 550 toilets for you, too) fringed by a mall for food and clubs. Michael Jackson was in rehearsal for a concert series for the O2 when he died, and during the 2012 Olympics, it housed gymnastics and basketball. For those not keen to squint at their favorite artist reduced to a tiny smudge on a distant arena stage, there’s O2 dome’s “intimate” performance space, IndigO2, although with 2,800 places in an acoustically superior, contemporary room, it’s still plenty big, has four bars, and attracts major talent (Prince, Leonard Cohen). Even if you aren’t carrying a ticket for a show, it’s worth exploring the massive open spaces inside. The bubbly-blue mega-chandelier hanging above the main entrance is too big for your camera’s viewfinder, but if you need something more jolting, you can take a safe, 2-hour climb above it on its Up at the O2 roof-walking attraction. One of the keys to O2’s explosive success has been the fact the Jubilee Line’s sleek North Greenwich station runs beneath it. Thames Clippers docks here, too.