The "Super-Sized" (DC's pun, not ours, for once) Superman Unchained #1 poster is unique. As artist Jim Lee told Newsarama, the poster is printed on a specially weighted paper, and held into the book using only the "dried rubber cement" style removable adhesive so that it can be hung by fans - but only after they read it!
The "pages," front and back, are made of four standard size pages - 11.6875” x 18.875” in total dimensions.
The release of Superman Unchained #1 by writer Scott Snyder and artist (and DC co-publisher) Jim Lee is set for June 12, 2013, two days before the release of the new Superman movie, Man of Steel, and what DC Comcis is styling "Man of Steel Day" in comic shops across the US, with special giveaways to go with the releases.
Check out the front half of the page, featuring a far pulled-out shot, on the right, then click the header image up top for the full back half of the page.