So when you come to see Passage (invitation will be on the way soon!) in the Verne, we are going to have to keep a tally of who goes in and who comes out, partly to ensure that noone gets left in the underground passageways, but also because this is a prison, and keeping account of numbers is high on the list of priorities. So you will be given a card when you enter which will be stamped, and then stamped a second time on exit. The question then is what should the stamp be: solved by looking above the south entrance to the prison and there, carved in stone, is this, along with the date 1881. Stamp solved!