The world's most compelling love affairs don't end in happily ever after. They end tragically, and by doing so, achieve immortality, reminding us of the fact that even though lovers may die, love itself remains forever. Whether on film, in literature or in real life, there have been many enduring tales of love found and lost. Romeo and Juliet, Sid and Nancy, Heathcliff and Catherine, John and Yoko, Ennis Del Mar and Jack Twist — their names are etched in golden letters in the history of mankind, as their stories reinforce the belief that true love is worth sacrificing everything.