This is going to sound morbid but I love visiting graveyards when I travel. Sometimes it's the closest you can get to celebrities. Some of my favorites include Père Lachaise Cemetery in Paris, the old graveyards of Boston (I love the artwork on the gravestones, so haunting) and Westwood in Beverly Hills (Marilyn Monroe and Natalie Wood's final resting place).
Père Lachaise remains my favorite...so grand and gorgeous and so many of the world's culturally elite all together in the same place.