Marco Polo's trip had, in fact, started more than 9,000 kilometers (5,600 miles) away in Venice when he was just a teenager His father and uncle already knew Kublai Khan from a previous visit five years earlier, when they had spent a short time in Shangdu. On this second trip the Polos would stay for 17 years, making themselves useful to the Khan and undertaking various missions and tasks for him. It is likely that the Khan considered it an honor that Europeans--who were rare in China had made the extremely difficult journey, and he made good use of thei skills and knowledge