Soup is a food that is made by combining ingredients such as meat, vegetables or legumes in stock or hot water, until the flavor is extracted, forming a broth.Traditionally, soups are classified into two broad groups: clear soups and thick soups. The established French classifications of clear soups are bouillon and consommé. Thick soups are classified depending upon the type of thickening agent used: purées are vegetable soups thickened with starch; bisques are made from puréed shellfish thickened with cream; cream soups are thickened with béchamel sauce; and veloutés are thickened with eggs, butter and cream. Other ingredients commonly used to thicken soups and broths include rice, flour, and grain.One of the first types of soups can be dated to about 6000 B.C. and was made of hippopotamus or the hearts of 5 sparrows. Boiling was not a common cooking technique until the invention of waterproof containers (which probably came in the form of pouches made of clay or animal skin) about 9,000 years ago.