The show isn’t until next month, but tickets already are on sale for an exhibition of more than 300 artifacts associated with Elvis Presley in what organizers say is the largest retrospective of the late rock ’n’ roll icon ever mounted in Europe. Elvis at The O2: The Exhibition of His Life, which runs Dec. 12 through Aug. 31, 2015 will chronicle Presley’s rise as the “King of Rock ’n’ Roll” and his impact on popular culture. Artifacts come from the Presley family’s Graceland archives. Some items have never been exhibited outside of Presley’s home-turned museum in Memphis, Tennessee. Items on display will include automobiles, historical documents, stage costumes, guitars and photos.