Having started as an informal gathering the year after his death, the vigil has now blossomed into a major tourist event. Fans begin lining up along the outer wall of Graceland about 12 hours before the vigil, and many stay until the early hours of the next day.

2013 marks the 36th anniversary of Elvis Presley's death. Fans from around the world have made their annual pilgrimage to Graceland, his home in Memphis, to pay their respects to the rock n' roll icon.

Nadine Kaslow, professor of psychiatry, Emory university, said, "Well, celebrity worship is not uncommon, but people choose only certain celebrities to worship and Elvis is one that has gotten some of the most amount of attention, even in his death. I think that people are drawn to the fact that he changed our culture and he did so in a way that was very appealing to other people. He was sort of socially engaging and he was eccentric and he was unique and he was creative and people are impressed by that and they're drawn to that."

Each year, fans of Presley's music and movies come to Memphis for Elvis Week, the weeklong celebration of his life and career. Presley died on Aug. 16, 1977, of a heart attack after battling prescription drug abuse.