" Ah, you agree? It has not been done, I think? And yet—it lends itself to romance, my friend. All around us are people, of all classes, of all nationalities, of all ages. For three days these people, these strangers to one another, are brought together. They sleep and eat under one roof, they cannot get away from each other. At the end of three days they part, they go their several ways, never, perhaps, to see each other again.” “And yet,” said Poirot, “suppose an accident—” “Ah no, my friend—” “From your point of view it would be regrettable, I agree. But nevertheless let us just for one moment suppose it. Then, perhaps, all these here are linked together—by death. "

― Agatha Christie , Murder on the Orient Express (Hercule Poirot, #9)