Potatoes were first domesticated in Peru and Chile 10,000 years ago, and later introduced to the British Isles. Very quickly they became an important part of the diet. It is an herbaceous annual that grows up to 100 cm tall and produces a tuber so rich in starch that it ranks as the world's fourth most important food crop, after maize, wheat and rice. Once harvested, potatoes are used for a variety of purposes, and not only as a vegetable for cooking at home. In fact, it is likely that less than 50 percent of potatoes grown worldwide are consumed fresh. The rest are processed into potato food products and food ingredients, fed to cattle, pigs and chickens, processed into starch for industry, and re-used as seed tubers for growing the next season's potato crop. Fresh potatoes are baked, boiled or fried and used in a staggering range of recipes: mashed potatoes, potato pancakes, potato dumplings, twice-baked potatoes, potato soup and potato salad.