Trade routes developed across Central Asia because of a desire for Chinese commodities in cultures west of the region, and for exotic goods in China itself. The most famous of the land trade routes is called the Silk Road. Beginning in Chang’an, the ancient Chinese capital, caravans made their way north and west toward the Chinese frontier. A north and a south route encircled the world’s second largest desert, the Taklamakan; both passed through oasis settlements, where travelers might be given access to the water in aqueducts and irrigation systems. The two routes rejoined near modern Kashgar and then led westward across the Pamir Mountains whose fifteen-thousand-foot passes were rarely clear of snow. The route crossed additional rough terrain before reaching the great Buddhist center of Bamiyan in modern Afghanistan. From there, routes diverged toward points further west, with some travelers even going as far as Rome. Sea routes increased in importance during and after the Tang dynasty (618-906). Many ships embarked on their voyages at Guangzhou (Canton) and other ports on the southeast coast of China. From there they traveled south along the coast of what is now Vietnam, west through the sea passages of Southeast Asia, and on to ports in Sri Lanka and along the coast of India. Goods were often transferred at these ports to other ships bound for Africa and Europe.