LOS ANGELES - Bob Marley's battle with cancer ended in a Miami hospital 30 years ago on Wednesday, bringing to a premature close the life of reggae music's most important standard-bearer.His son, David "Ziggy" Marley, who was 12 at the time and has gone on to reggae stardom in his own right, considers the anniversary a day for celebration rather than mourning."It's not the happiest day, but we've learned to live with it," he told Reuters on Wednesday. "The actual day is a day of journey. It's a day of movement. We accept it as that. We're not here to cry or to be sad. We're here to celebrate and be happy."Marley was on hand at the Grammy Museum where an exhibit about his father opened on Wednesday and runs through Oct. 2. The Marley family worked closely with the museum's curators, lending memorabilia from its personal collection.Perhaps the most significant item in the display is Marley's primary guitar, a modified mahogany Gibson Les Paul. The curators said it has never been displayed in the United States. The guitar is part of the permanent collection at the Bob Marley Museum in Kingston, Jamaica."That was his baby," Marley said. "That was his weapon. That's what he held closest to him onstage, offstage. It's made of wood, it's natural. Some of Bob's sweat, whatever, is in that wood, that guitar."He recalled that he used to play the guitar himself on stage until he was told it should be placed in the museum."I was very sad about that," he said with a laugh. "I wish I could still be jammin' on it."The exhibit also includes an embroidered blue denim stage jacket worn by Marley, as well as candid photographs, old concert posters and records. Music clips and video footage are also displayed, and drum machines allow visitors to try and play along with Marley's songs.Marley said the exhibition could be better appreciated while being high, a nod to Bob Marley's use of cannabis as one of the most high-profile adherents of the Rastafari movement."Spiritually high, or high on herb," he said. "But no drugs, though. No other thing. Natural high."The herb unifies a pair of new projects Ziggy Marley has been working on, a superhero comic book titled Marijuanaman and a new album called "Wild and Free."In the comic, Marijuanaman is forced to leave his planet after its natural supply of THC in the atmosphere is depleted. He lands on Earth, inevitably in a marijuana field, and is befriended by a community of environmentalists.The drug gives him super powers and he helps his friends battle an evil pharmaceutical company. He has a girlfriend, of course, named MJ, which is slang for marijuana.Actor and noted hemp advocate Woody Harrelson appears on the title track of the album, dueting with Marley in a spirited declaration of the beneficial effects of cannabis. It comes out on June 14.