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In 1274, Italian explorers Marco and Niccolo Polo set out on a 24-year journey in which they traveled the famous Silk Road from Italy, through brutal deserts and towering mountains to eastern China. They traveled over 4,000 miles in all. Marco and Niccolo were among the very first Europeans to explore the fabled empire of China. In China, Marco Polo even worked for ruler Kublai Khan. Polo detailed his experiences and findings in China by writing a book. Polo described materials and inventions never before seen in Europe. Paper money, a printing press, porcelain, gunpowder and coal were among the products he wrote about. He also described the vast wealth of Kublai Khan, as well as the geography of northern and southern China. European rulers were very interested in the products Polo described. However, trading for them along the Silk Road was dangerous, expensive and impractical. European rulers began to wonder if there was a sea route to the east to get the products they wanted at a reasonable price.