Most poetry events follow a familiar shape. There’s a room, a microphone, a row of chairs, and a polite round of applause between readers. It works, but it rarely surprises anyone. Every so often, though, an event comes along that rethinks the whole idea of what a poetry festival can be: not a showcase of finished work, but a place where the work actually gets made, out loud and in front of you. The Hold Space Poetry Festival, presented by The Crypt Gallery and Make Poetry Weird Again as part of Bloomsbury Festival’s 20th anniversary year, is one of those events. And it happens to take place underground, in a 200-year-old crypt, which helps.