British rockers Yes were the kind of torpid dinosaurs that punk was supposed to swallow, wash down with pints of snakebite and puke up as a horrid green mucus. Yet somehow the band, who once released the ridiculously overblown double album ‘Tales from Topographic Oceans’, continues to fill stadia on both sides of the Atlantic. Still featuring their original singer Jon Anderson, they recently celebrated the 30th anniversary of their first album by releasing a new one, ‘The Ladder’. Prog-rock still lives… but why?