The Polos-Marco,his father Niccolo, and his uncle Maffeo-had been traveling for three - and - a - half years when they finally achieved their objectives - a long - awaited meeting with the powerful Mongol leader, Kublai Khan. The historic event took place in 1275 at the Khan's luxurious summer capital in Shangdu, in what is now norhern China. As he greeted his tired guests, Kublai Khan was surprisingly informal: "How've you been? How was the trip?"