The Experience Music Project announced on Thursday plans to open the most extensive ehibit of Nirvana memorabilia in the world next April. The Seattle exhibit, called "Nirvana: Taking Punk to the Masses", will feature rare items like the reel-to-reels on which Kurt Cobain recorded his first demos and handwritten notes and snapshots submitted by members of the band.The exhibit will reportedly run from April 16th to April 22nd next year.