The Silk Road extends over 8,000 kms from China through Central Asia to the Mediterranean. The route acted as a highway for beliefs, ideas, inventions and art, whilst silk was just one of the many valuable commodities traded for 1,400 years. With the Greek invasion by Alexander the Great, early Persian routes spread east towards India. Chinese stability finally allowed the trade of silk, jade and ceramics in exchange for horses, pearls and gold. The wonderful paintings in the Magao caves at Dunhuang are evidence of the spread of Buddhism along the Silk Road. Samarkand and Bukhara are the beginning of the great Islamic buildings that continue through Persia and Syria.