For ten days this summer, the great geographical and cultural distance that lies between the heart of Europe and the far reaches of Asia is being reduced to the length of a leisurely afternoon stroll on the National Mall. For the first time in its 36-year history, the Smithsonian Folklife Festival has a single &emdash; and remarkably ambitious &emdash; theme: the Silk Road. The name denotes the network of trade routes, over both land and sea, along which merchants and travelers began to move across Asia and Europe from the first millennium B.C.E. The most famous east-west component of the Silk Road began in Xi'an, the ancient capital of China, broke north and south of China's Takla Makan Desert, and traversed a vast stretch of Central and Western Asia on its way to the eastern end of the Mediterranean. Along those staggering distances lay a wealth of cultures and traditions. They are still there; during the Folklife Festival, they come to life in the heart of Washington as well.