" 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. "

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