Saffron is known as the most expensive spice in the world. Prices vary depending on the quality as well as species. High-quality saffron can sell for as much as $ 6,000 per pound. The value of saffron results from its rarity and the intense labor ＿＿（31）＿＿ to harvest it. It takes 80,000 flowers to produce a pound of saffron. The harvest time is in autumn, and the process has to be carried out by hand. The history of saffron traces back to 4,000 years ago in Iran, ＿＿（32）＿＿ the spice was commonly used in the cuisines for the royal family. In the tenth century the cultivation of saffron was introduced to Spain by the Arabs. It is said that saffron was brought to Great Britain during the middle age by a pilgrim who hid a bulb of saffron in his stick and travelled from Middle East to Walden, a town 18 miles south of Cambridge. ＿＿（33）＿＿ the town's favorable soil and climate, saffron was widely grown there and gave prosperity to the town. Today most saffron comes from Iran, India, Turkey, Spain, Morocco, and Greece, among which Iran is responsible for 90% of the production worldwide. From ancient times saffron has been used in cooking and medicine. It is regarded as a(n) ＿＿（34）＿＿ ingredient for many regional specialties, including Spanish paella, Italian risotto, Saudi-Arabian coffee and tea, Indian curry, and Swedish saffron bread. Furthermore, this spice is used to treat diabetes, asthma, cough, kidney disorders, and skin diseases. It is also believed to be able to ＿＿（35）＿＿ the level of blood cholesterol and to prevent cancer.